<?php
/**
 * REST API: WP_REST_Attachments_Controller class
 *
 * @package WordPress
 * @subpackage REST_API
 * @since 4.7.0
 */

/**
 * Core controller used to access attachments via the REST API.
 *
 * @since 4.7.0
 *
 * @see WP_REST_Posts_Controller
 *
 * @phpstan-type Image_Sub_Size array{
 *     image_size: non-empty-string|non-empty-list<non-empty-string>,
 *     width?: positive-int,
 *     height?: positive-int,
 *     file?: non-empty-string,
 *     mime_type?: non-empty-string,
 *     filesize?: positive-int,
 *     original_image?: non-empty-string,
 * }
 */
class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {

	/**
	 * Whether the controller supports batching.
	 *
	 * @since 5.9.0
	 * @var false
	 */
	protected $allow_batch = false;

	/**
	 * Image size token for the source-format original preserved alongside a
	 * client-generated derivative (e.g. the HEIC file kept next to its JPEG).
	 *
	 * Used both in the `/sideload` route schema and when dispatching the
	 * sideloaded file to its metadata key, so the two never drift apart.
	 *
	 * @since 7.1.0
	 * @var string
	 */
	const IMAGE_SIZE_SOURCE_ORIGINAL = 'source_original';

	/**
	 * Metadata key holding the basename of the source-format original.
	 *
	 * Deliberately specific so it never collides with the generic `original`
	 * or `original_image` keys other flows write to.
	 *
	 * @since 7.1.0
	 * @var string
	 */
	const META_KEY_SOURCE_IMAGE = 'source_image';

	/**
	 * Post meta key recording the file names produced by the sideload endpoint.
	 *
	 * Each successful sideload appends the file name(s) it created for an
	 * attachment under this key. The finalize endpoint reads them back to
	 * confirm every stored sub-size was actually produced here, rather than
	 * trusting a client-supplied name that could point at another attachment's
	 * files. Stored as one row per value (via {@see add_post_meta()}) so concurrent
	 * sideloads never read-modify-write a shared value.
	 *
	 * @since 7.1.0
	 * @var string
	 */
	const META_KEY_SIDELOAD_FILE_NAME = '_wp_sideloaded_file';

	/**
	 * Registers the routes for attachments.
	 *
	 * @since 5.3.0
	 *
	 * @see register_rest_route()
	 */
	public function register_routes() {
		parent::register_routes();
		register_rest_route(
			$this->namespace,
			'/' . $this->rest_base . '/(?P<id>[\d]+)/post-process',
			array(
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'post_process_item' ),
				'permission_callback' => array( $this, 'post_process_item_permissions_check' ),
				'args'                => array(
					'id'     => array(
						'description' => __( 'Unique identifier for the attachment.' ),
						'type'        => 'integer',
					),
					'action' => array(
						'type'     => 'string',
						'enum'     => array( 'create-image-subsizes' ),
						'required' => true,
					),
				),
			)
		);
		register_rest_route(
			$this->namespace,
			'/' . $this->rest_base . '/(?P<id>[\d]+)/edit',
			array(
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'edit_media_item' ),
				'permission_callback' => array( $this, 'edit_media_item_permissions_check' ),
				'args'                => $this->get_edit_media_item_args(),
			)
		);

		if ( wp_is_client_side_media_processing_enabled() ) {
			register_rest_route(
				$this->namespace,
				'/' . $this->rest_base . '/(?P<id>[\d]+)/sideload',
				array(
					array(
						'methods'             => WP_REST_Server::CREATABLE,
						'callback'            => array( $this, 'sideload_item' ),
						'permission_callback' => array( $this, 'sideload_item_permissions_check' ),
						'args'                => array(
							'id'             => array(
								'description' => __( 'Unique identifier for the attachment.' ),
								'type'        => 'integer',
							),
							'image_size'     => array(
								'description'       => __( 'Image size. Can be a single size name or an array of size names to register the same file under multiple sizes.' ),
								'type'              => array( 'string', 'array' ),
								'items'             => array(
									'type'      => 'string',
									'minLength' => 1,
								),
								'minItems'          => 1,
								'minLength'         => 1,
								'required'          => true,
								/*
								 * A custom callback is used instead of the default enum validation
								 * because rest_is_array() treats scalar strings as single-element
								 * lists (via wp_parse_list()), so a [ 'string', 'array' ] type alone
								 * cannot enforce the enum. The callback validates each item against
								 * the current list of registered sizes, which reflects sizes added
								 * after route registration (e.g. via add_image_size()).
								 */
								'validate_callback' => static function ( $value, WP_REST_Request $request, string $param ) {
									/*
									 * Providing a custom callback replaces the default schema
									 * validation, so apply the declared schema (type, minLength,
									 * minItems) before the enum check below.
									 */
									$schema_validity = rest_validate_request_arg( $value, $request, $param );
									if ( is_wp_error( $schema_validity ) ) {
										return $schema_validity;
									}

									return self::validate_image_size_names( $value, $param );
								},
							),
							'convert_format' => array(
								'type'        => 'boolean',
								'default'     => true,
								'description' => __( 'Whether to convert image formats.' ),
							),
						),
					),
					'allow_batch' => $this->allow_batch,
					'schema'      => array( $this, 'get_public_item_schema' ),
				)
			);

			register_rest_route(
				$this->namespace,
				'/' . $this->rest_base . '/(?P<id>[\d]+)/finalize',
				array(
					array(
						'methods'             => WP_REST_Server::CREATABLE,
						'callback'            => array( $this, 'finalize_item' ),
						'permission_callback' => array( $this, 'edit_media_item_permissions_check' ),
						'args'                => array(
							'id'        => array(
								'description' => __( 'Unique identifier for the attachment.' ),
								'type'        => 'integer',
							),
							'sub_sizes' => array(
								'description'       => __( 'Array of sub-size metadata collected from sideload responses.' ),
								'type'              => 'array',
								'default'           => array(),
								/*
								 * A finalize request sends one entry per sideloaded sub-size, so
								 * the ceiling only needs to clear the number of sizes a site can
								 * register. Bounding it keeps a request from repeating a name
								 * across an arbitrary number of entries.
								 */
								'maxItems'          => 100,
								/*
								 * As on the sideload endpoint, the size names are checked in a
								 * callback rather than an enum, so the set reflects the sizes
								 * registered when the request runs. The callback sits on
								 * sub_sizes because a nested property cannot carry one.
								 */
								'validate_callback' => static function ( $value, WP_REST_Request $request, string $param ) {
									/*
									 * Providing a custom callback replaces the default schema
									 * validation, so apply the declared schema first. That is what
									 * guarantees each entry is an object carrying an image_size of
									 * the declared type.
									 */
									$schema_validity = rest_validate_request_arg( $value, $request, $param );
									if ( is_wp_error( $schema_validity ) ) {
										return $schema_validity;
									}

									foreach ( (array) $value as $index => $sub_size ) {
										$sub_size = (array) $sub_size;

										$validity = self::validate_image_size_names(
											$sub_size['image_size'] ?? null,
											sprintf( '%s[%s][image_size]', $param, $index )
										);

										if ( is_wp_error( $validity ) ) {
											return $validity;
										}
									}

									return true;
								},
								'items'             => array(
									'type'       => 'object',
									'properties' => array(
										'image_size'     => array(
											'description' => __( 'Size name, or an array of size names when a single file is registered under multiple sizes with matching dimensions.' ),
											'type'        => array( 'string', 'array' ),
											'items'       => array(
												'type' => 'string',
												'minLength' => 1,
											),
											'minItems'    => 1,
											'minLength'   => 1,
											'required'    => true,
										),
										'width'          => array(
											'type'    => 'integer',
											'minimum' => 1,
										),
										'height'         => array(
											'type'    => 'integer',
											'minimum' => 1,
										),
										'file'           => array(
											'type'      => 'string',
											'minLength' => 1,
										),
										'mime_type'      => array(
											'type'    => 'string',
											'pattern' => '^image/.*',
										),
										'filesize'       => array(
											'type'    => 'integer',
											'minimum' => 1,
										),
										'original_image' => array(
											'type'      => 'string',
											'minLength' => 1,
										),
									),
								),
							),
						),
					),
					'allow_batch' => $this->allow_batch,
					'schema'      => array( $this, 'get_public_item_schema' ),
				)
			);
		}
	}

	/**
	 * Retrieves the query params for the attachments collection.
	 *
	 * @since 7.1.0
	 *
	 * @param string $method Optional. HTTP method of the request.
	 *                       The arguments for `CREATABLE` requests are
	 *                       checked for required values and may fall-back to a given default.
	 *                       Default WP_REST_Server::CREATABLE.
	 * @return array<string, array<string, mixed>> Endpoint arguments.
	 */
	public function get_endpoint_args_for_item_schema( $method = WP_REST_Server::CREATABLE ) {
		$args = parent::get_endpoint_args_for_item_schema( $method );

		if ( WP_REST_Server::CREATABLE !== $method ) {
			return $args;
		}

		$args['generate_sub_sizes'] = array(
			'type'        => 'boolean',
			'default'     => true,
			'description' => __( 'Whether to generate image sub sizes.' ),
		);

		$args['convert_format'] = array(
			'type'        => 'boolean',
			'default'     => true,
			'description' => __( 'Whether to convert image formats.' ),
		);

		$args['url'] = array(
			'type'              => 'string',
			'format'            => 'uri',
			'description'       => __( 'URL of an external image to sideload into the media library, instead of uploading a file.' ),
			'sanitize_callback' => 'sanitize_url',
			'validate_callback' => static function ( $url, $request, $param ) {
				/*
				 * A custom validate_callback replaces the default
				 * rest_validate_request_arg(), so re-apply it first to keep
				 * the schema checks (string type, uri format) enforced.
				 */
				$valid = rest_validate_request_arg( $url, $request, $param );
				if ( is_wp_error( $valid ) ) {
					return $valid;
				}

				/*
				 * Reject URLs that are not safe to request server-side. wp_http_validate_url()
				 * enforces an HTTP(S) scheme and blocks private, local, and otherwise
				 * disallowed hosts, guarding the sideload against SSRF.
				 */
				if ( false === wp_http_validate_url( $url ) ) {
					return new WP_Error(
						'rest_invalid_url',
						__( 'Invalid URL. Provide a valid, publicly reachable HTTP or HTTPS image URL.' ),
						array( 'status' => 400 )
					);
				}

				return true;
			},
		);

		return $args;
	}

	/**
	 * Determines the allowed query_vars for a get_items() response and
	 * prepares for WP_Query.
	 *
	 * @since 4.7.0
	 * @since 6.9.0 Extends the `media_type` and `mime_type` request arguments to support array values.
	 *
	 * @param array           $prepared_args Optional. Array of prepared arguments. Default empty array.
	 * @param WP_REST_Request $request       Optional. Request to prepare items for.
	 * @return array Array of query arguments.
	 */
	protected function prepare_items_query( $prepared_args = array(), $request = null ) {
		$query_args = parent::prepare_items_query( $prepared_args, $request );

		if ( empty( $query_args['post_status'] ) ) {
			$query_args['post_status'] = 'inherit';
		}

		$all_mime_types = array();
		$media_types    = $this->get_media_types();

		if ( ! empty( $request['media_type'] ) && is_array( $request['media_type'] ) ) {
			foreach ( $request['media_type'] as $type ) {
				if ( isset( $media_types[ $type ] ) ) {
					$all_mime_types = array_merge( $all_mime_types, $media_types[ $type ] );
				}
			}
		}

		if ( ! empty( $request['mime_type'] ) && is_array( $request['mime_type'] ) ) {
			foreach ( $request['mime_type'] as $mime_type ) {
				$parts = explode( '/', $mime_type );
				if ( isset( $media_types[ $parts[0] ] ) && in_array( $mime_type, $media_types[ $parts[0] ], true ) ) {
					$all_mime_types[] = $mime_type;
				}
			}
		}

		if ( ! empty( $all_mime_types ) ) {
			$query_args['post_mime_type'] = array_values( array_unique( $all_mime_types ) );
		}

		// Filter query clauses to include filenames.
		if ( isset( $query_args['s'] ) ) {
			add_filter( 'wp_allow_query_attachment_by_filename', '__return_true' );
		}

		return $query_args;
	}

	/**
	 * Checks if a given request has access to create an attachment.
	 *
	 * @since 4.7.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error Boolean true if the attachment may be created, or a WP_Error if not.
	 */
	public function create_item_permissions_check( $request ) {
		$ret = parent::create_item_permissions_check( $request );

		if ( ! $ret || is_wp_error( $ret ) ) {
			return $ret;
		}

		if ( ! current_user_can( 'upload_files' ) ) {
			return new WP_Error(
				'rest_cannot_create',
				__( 'Sorry, you are not allowed to upload media on this site.' ),
				array( 'status' => 400 )
			);
		}

		// Attaching media to a post requires ability to edit said post.
		if ( ! empty( $request['post'] ) && ! current_user_can( 'edit_post', (int) $request['post'] ) ) {
			return new WP_Error(
				'rest_cannot_edit',
				__( 'Sorry, you are not allowed to upload media to this post.' ),
				array( 'status' => rest_authorization_required_code() )
			);
		}
		$files = $request->get_file_params();

		/**
		 * Filter whether the server should prevent uploads for image types it doesn't support. Default true.
		 *
		 * Developers can use this filter to enable uploads of certain image types. By default image types that are not
		 * supported by the server are prevented from being uploaded.
		 *
		 * @since 6.8.0
		 *
		 * @param bool        $check_mime Whether to prevent uploads of unsupported image types.
		 * @param string|null $mime_type  The mime type of the file being uploaded (if available).
		 */
		$prevent_unsupported_uploads = apply_filters( 'wp_prevent_unsupported_mime_type_uploads', true, $files['file']['type'] ?? null );

		/*
		 * When the client handles image processing (generate_sub_sizes is false),
		 * skip the server-side image editor support check. This check exists
		 * because the server cannot process the image, so it is only relaxed when
		 * client side media processing is enabled and something else can. Asking
		 * to skip sub sizes on a site without it does not make an unsupported
		 * image type any more usable.
		 */
		if ( wp_is_client_side_media_processing_enabled() && false === $request['generate_sub_sizes'] ) {
			$prevent_unsupported_uploads = false;
		}

		/*
		 * Always allow still HEIC/HEIF uploads through even if the server's
		 * image editor doesn't support them. The client-side canvas fallback
		 * handles processing using the browser's native HEVC decoder.
		 *
		 * The '-sequence' variants (multi-frame Live Photos) are deliberately
		 * excluded: neither the server nor the browser fallback can process
		 * them yet, so they should fall through to the standard unsupported
		 * mime-type error rather than be stored unprocessable.
		 */
		$still_heic_mime_types = array( 'image/heic', 'image/heif' );

		if (
			$prevent_unsupported_uploads &&
			! empty( $files['file']['type'] ) &&
			in_array( $files['file']['type'], $still_heic_mime_types, true )
		) {
			$prevent_unsupported_uploads = false;
		}

		// If the upload is an image, check if the server can handle the mime type.
		if (
			$prevent_unsupported_uploads &&
			isset( $files['file']['type'] ) &&
			str_starts_with( $files['file']['type'], 'image/' )
		) {
			// List of non-resizable image formats.
			$editor_non_resizable_formats = array(
				'image/svg+xml',
			);

			// Check if the image editor supports the type or ignore if it isn't a format resizable by an editor.
			if (
				! in_array( $files['file']['type'], $editor_non_resizable_formats, true ) &&
				! wp_image_editor_supports( array( 'mime_type' => $files['file']['type'] ) )
			) {
				return new WP_Error(
					'rest_upload_image_type_not_supported',
					__( 'The web server cannot generate responsive image sizes for this image. Convert it to JPEG or PNG before uploading.' ),
					array( 'status' => 400 )
				);
			}
		}

		return true;
	}

	/**
	 * Creates a single attachment.
	 *
	 * @since 4.7.0
	 * @since 7.1.0 Added the `generate_sub_sizes`, `convert_format`, and `url` parameters.
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function create_item( $request ) {
		if ( ! empty( $request['post'] ) && in_array( get_post_type( $request['post'] ), array( 'revision', 'attachment' ), true ) ) {
			return new WP_Error(
				'rest_invalid_param',
				__( 'Invalid parent type.' ),
				array( 'status' => 400 )
			);
		}

		// Handle generate_sub_sizes parameter.
		if ( false === $request['generate_sub_sizes'] ) {
			add_filter( 'intermediate_image_sizes_advanced', '__return_empty_array', 100 );
			add_filter( 'fallback_intermediate_image_sizes', '__return_empty_array', 100 );
			// Disable server-side EXIF rotation so the client can handle it.
			// This preserves the original orientation value in the metadata.
			add_filter( 'wp_image_maybe_exif_rotate', '__return_false', 100 );
			// Disable server-side "big image" downscaling; the client supplies its
			// own scaled version via the sideload endpoint. Scaling here would
			// create a conflicting "-scaled" file and orphan the full-size upload.
			add_filter( 'big_image_size_threshold', '__return_false', 100 );
		}

		// Handle convert_format parameter.
		if ( false === $request['convert_format'] ) {
			add_filter( 'image_editor_output_format', '__return_empty_array', 100 );
		}

		/*
		 * When a URL is supplied instead of an uploaded file, sideload the
		 * remote image on the server. This avoids a cross-origin browser fetch,
		 * which fails under cross-origin isolation. The sub-size and scaling
		 * filters applied above still govern whether derivatives are generated.
		 */
		if ( ! empty( $request['url'] ) ) {
			$response = $this->create_item_from_url( $request );
			$this->remove_client_side_media_processing_filters();
			return $response;
		}

		$insert = $this->insert_attachment( $request );

		if ( is_wp_error( $insert ) ) {
			$this->remove_client_side_media_processing_filters();
			return $insert;
		}

		$schema = $this->get_item_schema();

		// Extract by name.
		$attachment_id = $insert['attachment_id'];
		$file          = $insert['file'];

		if ( isset( $request['alt_text'] ) ) {
			update_post_meta( $attachment_id, '_wp_attachment_image_alt', sanitize_text_field( $request['alt_text'] ) );
		}

		if ( ! empty( $schema['properties']['featured_media'] ) && isset( $request['featured_media'] ) ) {
			$thumbnail_update = $this->handle_featured_media( $request['featured_media'], $attachment_id );

			if ( is_wp_error( $thumbnail_update ) ) {
				$this->remove_client_side_media_processing_filters();
				return $thumbnail_update;
			}
		}

		if ( ! empty( $schema['properties']['meta'] ) && isset( $request['meta'] ) ) {
			$meta_update = $this->meta->update_value( $request['meta'], $attachment_id );

			if ( is_wp_error( $meta_update ) ) {
				$this->remove_client_side_media_processing_filters();
				return $meta_update;
			}
		}

		$attachment    = get_post( $attachment_id );
		$fields_update = $this->update_additional_fields_for_object( $attachment, $request );

		if ( is_wp_error( $fields_update ) ) {
			$this->remove_client_side_media_processing_filters();
			return $fields_update;
		}

		$terms_update = $this->handle_terms( $attachment_id, $request );

		if ( is_wp_error( $terms_update ) ) {
			$this->remove_client_side_media_processing_filters();
			return $terms_update;
		}

		$request->set_param( 'context', 'edit' );

		/**
		 * Fires after a single attachment is completely created or updated via the REST API.
		 *
		 * @since 5.0.0
		 *
		 * @param WP_Post         $attachment Inserted or updated attachment object.
		 * @param WP_REST_Request $request    Request object.
		 * @param bool            $creating   True when creating an attachment, false when updating.
		 */
		do_action( 'rest_after_insert_attachment', $attachment, $request, true );

		wp_after_insert_post( $attachment, false, null );

		if ( wp_is_serving_rest_request() ) {
			/*
			 * Set a custom header with the attachment_id.
			 * Used by the browser/client to resume creating image sub-sizes after a PHP fatal error.
			 */
			header( 'X-WP-Upload-Attachment-ID: ' . $attachment_id );
		}

		// Include media and image functions to get access to wp_generate_attachment_metadata().
		require_once ABSPATH . 'wp-admin/includes/media.php';
		require_once ABSPATH . 'wp-admin/includes/image.php';

		/*
		 * Post-process the upload (create image sub-sizes, make PDF thumbnails, etc.) and insert attachment meta.
		 * At this point the server may run out of resources and post-processing of uploaded images may fail.
		 */
		wp_update_attachment_metadata( $attachment_id, wp_generate_attachment_metadata( $attachment_id, $file ) );

		$this->remove_client_side_media_processing_filters();

		$response = $this->prepare_item_for_response( $attachment, $request );
		$response = rest_ensure_response( $response );
		$response->set_status( 201 );
		$response->header( 'Location', rest_url( sprintf( '%s/%s/%d', $this->namespace, $this->rest_base, $attachment_id ) ) );

		return $response;
	}

	/**
	 * Sideloads an external image from a URL into the media library.
	 *
	 * Downloads the remote file on the server, avoiding a cross-origin browser
	 * fetch that fails under cross-origin isolation. Whether sub-sizes are
	 * generated is governed by the filters applied in create_item().
	 *
	 * @since 7.1.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	protected function create_item_from_url( WP_REST_Request $request ) {
		// Sideloading downloads and stores a file, so require the upload capability.
		if ( ! current_user_can( 'upload_files' ) ) {
			return new WP_Error(
				'rest_cannot_create',
				__( 'Sorry, you are not allowed to upload media on this site.' ),
				array( 'status' => rest_authorization_required_code() )
			);
		}

		require_once ABSPATH . 'wp-admin/includes/file.php';
		require_once ABSPATH . 'wp-admin/includes/media.php';
		require_once ABSPATH . 'wp-admin/includes/image.php';

		$url     = $request['url'];
		$post_id = ! empty( $request['post'] ) ? (int) $request['post'] : 0;

		// Derive the filename from the URL path before downloading anything.
		$url_path = wp_parse_url( $url, PHP_URL_PATH );
		$filename = $url_path ? wp_basename( $url_path ) : '';
		if ( '' === $filename ) {
			return new WP_Error(
				'rest_invalid_url',
				__( 'Could not determine a filename from the provided URL.' ),
				array( 'status' => 400 )
			);
		}

		/*
		 * Only download URLs whose extension maps to an allowed image MIME type.
		 * The sideload handler would reject other types anyway (via
		 * wp_check_filetype_and_ext()), but checking first avoids downloading
		 * files that can never be accepted, such as PHP scripts.
		 */
		$filetype = wp_check_filetype( $filename );
		if ( ! $filetype['type'] || ! str_starts_with( $filetype['type'], 'image/' ) ) {
			return new WP_Error(
				'rest_invalid_url',
				__( 'The provided URL does not point to a supported image file.' ),
				array( 'status' => 400 )
			);
		}

		/*
		 * Cap the download at the same size the site would accept as a direct
		 * upload. check_upload_size() only applies on multisite, so without a
		 * ceiling here a single site has no limit at all on this path: the
		 * `upload_max_filesize` and `post_max_size` directives bound a request
		 * body, not a fetch the server makes itself.
		 *
		 * When `wp_max_upload_size` returns 0, no ceiling is applied.
		 */
		$max_size = (int) wp_max_upload_size();

		/*
		 * Download the remote file with WordPress's HTTP API, which validates
		 * the host and blocks requests to private or local addresses. This is
		 * the same primitive core's media_sideload_image() relies on.
		 *
		 * `limit_response_size` stops the transfer once the limit is passed,
		 * so an oversized remote file is never written to disk in full. One
		 * byte over the ceiling is enough to fail the size check below.
		 */
		$limit_response_size = static function ( $args ) use ( $max_size ) {
			$args['limit_response_size'] = $max_size + 1;
			return $args;
		};

		if ( $max_size > 0 ) {
			add_filter( 'http_request_args', $limit_response_size );
		}

		$tmp_file = download_url( $url );

		if ( $max_size > 0 ) {
			remove_filter( 'http_request_args', $limit_response_size );
		}

		if ( is_wp_error( $tmp_file ) ) {
			return $tmp_file;
		}

		$file_array = array(
			'name'     => $filename,
			'tmp_name' => $tmp_file,
		);

		$size_check = self::check_upload_size( $file_array );
		if ( is_wp_error( $size_check ) ) {
			if ( file_exists( $tmp_file ) ) {
				wp_delete_file( $tmp_file );
			}
			return $size_check;
		}

		if ( $max_size > 0 && wp_filesize( $tmp_file ) > $max_size ) {
			if ( file_exists( $tmp_file ) ) {
				wp_delete_file( $tmp_file );
			}

			return new WP_Error(
				'rest_upload_file_too_big',
				/* translators: %s: Maximum allowed file size in kilobytes. */
				sprintf( __( 'This file is too big. Files must be less than %s KB in size.' ), number_format( $max_size / KB_IN_BYTES ) ),
				array( 'status' => 400 )
			);
		}

		$attachment_id = media_handle_sideload( $file_array, $post_id );

		if ( is_wp_error( $attachment_id ) ) {
			/*
			 * media_handle_sideload() deletes the temp file on success; remove
			 * it explicitly when the sideload fails.
			 */
			if ( file_exists( $tmp_file ) ) {
				wp_delete_file( $tmp_file );
			}
			return $attachment_id;
		}

		$attachment = get_post( $attachment_id );

		$request->set_param( 'context', 'edit' );

		/*
		 * media_handle_sideload() fires the standard insert hooks (including
		 * wp_after_insert_post), but not the REST-specific action, so fire it
		 * here for parity with the uploaded-file path in create_item().
		 */
		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php */
		do_action( 'rest_after_insert_attachment', $attachment, $request, true );

		$response = $this->prepare_item_for_response( $attachment, $request );
		$response->set_status( 201 );
		$response->header( 'Location', rest_url( rest_get_route_for_post( $attachment_id ) ) );

		return $response;
	}

	/**
	 * Removes filters added for client-side media processing.
	 *
	 * @since 7.1.0
	 */
	private function remove_client_side_media_processing_filters(): void {
		remove_filter( 'intermediate_image_sizes_advanced', '__return_empty_array', 100 );
		remove_filter( 'fallback_intermediate_image_sizes', '__return_empty_array', 100 );
		remove_filter( 'wp_image_maybe_exif_rotate', '__return_false', 100 );
		remove_filter( 'image_editor_output_format', '__return_empty_array', 100 );
		remove_filter( 'big_image_size_threshold', '__return_false', 100 );
	}

	/**
	 * Inserts the attachment post in the database. Does not update the attachment meta.
	 *
	 * @since 5.3.0
	 *
	 * @param WP_REST_Request $request
	 * @return array|WP_Error
	 */
	protected function insert_attachment( $request ) {
		// Get the file via $_FILES or raw data.
		$files   = $request->get_file_params();
		$headers = $request->get_headers();

		$time = null;

		// Matches logic in media_handle_upload().
		if ( ! empty( $request['post'] ) ) {
			$post = get_post( $request['post'] );
			// The post date doesn't usually matter for pages, so don't backdate this upload.
			if ( $post && 'page' !== $post->post_type && substr( $post->post_date, 0, 4 ) > 0 ) {
				$time = $post->post_date;
			}
		}

		if ( ! empty( $files ) ) {
			$file = $this->upload_from_file( $files, $headers, $time );
		} else {
			$file = $this->upload_from_data( $request->get_body(), $headers, $time );
		}

		if ( is_wp_error( $file ) ) {
			return $file;
		}

		$name       = wp_basename( $file['file'] );
		$name_parts = pathinfo( $name );
		$name       = trim( substr( $name, 0, -( 1 + strlen( $name_parts['extension'] ) ) ) );

		$url  = $file['url'];
		$type = $file['type'];
		$file = $file['file'];
		$alt  = '';

		// Include image functions to get access to wp_read_image_metadata().
		require_once ABSPATH . 'wp-admin/includes/image.php';

		// Use image exif/iptc data for title and caption defaults if possible.
		$image_meta = wp_read_image_metadata( $file );

		if ( ! empty( $image_meta ) ) {
			if ( empty( $request['title'] ) && trim( $image_meta['title'] ) && ! is_numeric( sanitize_title( $image_meta['title'] ) ) ) {
				$request['title'] = $image_meta['title'];
			}

			if ( empty( $request['caption'] ) && trim( $image_meta['caption'] ) ) {
				$request['caption'] = $image_meta['caption'];
			}

			if ( empty( $request['alt'] ) && trim( $image_meta['alt'] ) ) {
				$alt = $image_meta['alt'];
			}
		}

		$attachment = $this->prepare_item_for_database( $request );

		$attachment->post_mime_type = $type;
		$attachment->guid           = $url;

		// If the title was not set, use the original filename.
		if ( empty( $attachment->post_title ) && ! empty( $files['file']['name'] ) ) {
			// Remove the file extension (after the last `.`)
			$tmp_title = substr( $files['file']['name'], 0, strrpos( $files['file']['name'], '.' ) );

			if ( ! empty( $tmp_title ) ) {
				$attachment->post_title = $tmp_title;
			}
		}

		// Fall back to the original approach.
		if ( empty( $attachment->post_title ) ) {
			$attachment->post_title = preg_replace( '/\.[^.]+$/', '', wp_basename( $file ) );
		}

		// $post_parent is inherited from $attachment['post_parent'].
		$id = wp_insert_attachment( wp_slash( (array) $attachment ), $file, 0, true, false );

		if ( trim( $alt ) ) {
			update_post_meta( $id, '_wp_attachment_image_alt', sanitize_text_field( $alt ) );
		}

		if ( is_wp_error( $id ) ) {
			if ( 'db_update_error' === $id->get_error_code() ) {
				$id->add_data( array( 'status' => 500 ) );
			} else {
				$id->add_data( array( 'status' => 400 ) );
			}

			return $id;
		}

		$attachment = get_post( $id );

		/**
		 * Fires after a single attachment is created or updated via the REST API.
		 *
		 * @since 4.7.0
		 *
		 * @param WP_Post         $attachment Inserted or updated attachment object.
		 * @param WP_REST_Request $request    The request sent to the API.
		 * @param bool            $creating   True when creating an attachment, false when updating.
		 */
		do_action( 'rest_insert_attachment', $attachment, $request, true );

		return array(
			'attachment_id' => $id,
			'file'          => $file,
		);
	}

	/**
	 * Determines the featured media based on a request param.
	 *
	 * @since 6.5.0
	 *
	 * @param int $featured_media Featured Media ID.
	 * @param int $post_id        Post ID.
	 * @return bool|WP_Error Whether the post thumbnail was successfully deleted, otherwise WP_Error.
	 */
	protected function handle_featured_media( $featured_media, $post_id ) {
		$post_type         = get_post_type( $post_id );
		$thumbnail_support = current_theme_supports( 'post-thumbnails', $post_type ) && post_type_supports( $post_type, 'thumbnail' );

		// Similar check as in wp_insert_post().
		if ( ! $thumbnail_support && get_post_mime_type( $post_id ) ) {
			if ( wp_attachment_is( 'audio', $post_id ) ) {
				$thumbnail_support = post_type_supports( 'attachment:audio', 'thumbnail' ) || current_theme_supports( 'post-thumbnails', 'attachment:audio' );
			} elseif ( wp_attachment_is( 'video', $post_id ) ) {
				$thumbnail_support = post_type_supports( 'attachment:video', 'thumbnail' ) || current_theme_supports( 'post-thumbnails', 'attachment:video' );
			}
		}

		if ( $thumbnail_support ) {
			return parent::handle_featured_media( $featured_media, $post_id );
		}

		return new WP_Error(
			'rest_no_featured_media',
			sprintf(
				/* translators: %s: attachment mime type */
				__( 'This site does not support post thumbnails on attachments with MIME type %s.' ),
				get_post_mime_type( $post_id )
			),
			array( 'status' => 400 )
		);
	}

	/**
	 * Updates a single attachment.
	 *
	 * @since 4.7.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function update_item( $request ) {
		if ( ! empty( $request['post'] ) && in_array( get_post_type( $request['post'] ), array( 'revision', 'attachment' ), true ) ) {
			return new WP_Error(
				'rest_invalid_param',
				__( 'Invalid parent type.' ),
				array( 'status' => 400 )
			);
		}

		$attachment_before = get_post( $request['id'] );
		$response          = parent::update_item( $request );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		$response = rest_ensure_response( $response );
		$data     = $response->get_data();

		if ( isset( $request['alt_text'] ) ) {
			update_post_meta( $data['id'], '_wp_attachment_image_alt', $request['alt_text'] );
		}

		$attachment = get_post( $request['id'] );

		if ( ! empty( $schema['properties']['featured_media'] ) && isset( $request['featured_media'] ) ) {
			$thumbnail_update = $this->handle_featured_media( $request['featured_media'], $attachment->ID );

			if ( is_wp_error( $thumbnail_update ) ) {
				return $thumbnail_update;
			}
		}

		$fields_update = $this->update_additional_fields_for_object( $attachment, $request );

		if ( is_wp_error( $fields_update ) ) {
			return $fields_update;
		}

		$request->set_param( 'context', 'edit' );

		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php */
		do_action( 'rest_after_insert_attachment', $attachment, $request, false );

		wp_after_insert_post( $attachment, true, $attachment_before );

		$response = $this->prepare_item_for_response( $attachment, $request );
		$response = rest_ensure_response( $response );

		return $response;
	}

	/**
	 * Performs post-processing on an attachment.
	 *
	 * @since 5.3.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function post_process_item( $request ) {
		switch ( $request['action'] ) {
			case 'create-image-subsizes':
				require_once ABSPATH . 'wp-admin/includes/image.php';
				wp_update_image_subsizes( $request['id'] );
				break;
		}

		$request['context'] = 'edit';

		return $this->prepare_item_for_response( get_post( $request['id'] ), $request );
	}

	/**
	 * Checks if a given request can perform post-processing on an attachment.
	 *
	 * @since 5.3.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True if the request has access to update the item, WP_Error object otherwise.
	 */
	public function post_process_item_permissions_check( $request ) {
		return $this->update_item_permissions_check( $request );
	}

	/**
	 * Checks if a given request has access to editing media.
	 *
	 * @since 5.5.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
	 */
	public function edit_media_item_permissions_check( $request ) {
		if ( ! current_user_can( 'upload_files' ) ) {
			return new WP_Error(
				'rest_cannot_edit_image',
				__( 'Sorry, you are not allowed to upload media on this site.' ),
				array( 'status' => rest_authorization_required_code() )
			);
		}

		return $this->update_item_permissions_check( $request );
	}

	/**
	 * Applies edits to a media item and creates a new attachment record.
	 *
	 * @since 5.5.0
	 * @since 6.9.0 Adds flips capability and editable fields for the newly-created attachment post.
	 * @since 7.1.0 Applies EXIF orientation correction before image modifications.
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function edit_media_item( $request ) {
		require_once ABSPATH . 'wp-admin/includes/image.php';

		$attachment_id = $request['id'];

		// This also confirms the attachment is an image.
		$image_file = wp_get_original_image_path( $attachment_id );
		$image_meta = wp_get_attachment_metadata( $attachment_id );

		if (
			! $image_meta ||
			! $image_file ||
			! wp_image_file_matches_image_meta( $request['src'], $image_meta, $attachment_id )
		) {
			return new WP_Error(
				'rest_unknown_attachment',
				__( 'Unable to get meta information for file.' ),
				array( 'status' => 404 )
			);
		}

		$supported_types = array( 'image/jpeg', 'image/png', 'image/gif', 'image/webp', 'image/avif', 'image/heic' );
		$mime_type       = get_post_mime_type( $attachment_id );
		if ( ! in_array( $mime_type, $supported_types, true ) ) {
			return new WP_Error(
				'rest_cannot_edit_file_type',
				__( 'This type of file cannot be edited.' ),
				array( 'status' => 400 )
			);
		}

		// The `modifiers` param takes precedence over the older format.
		if ( isset( $request['modifiers'] ) ) {
			$modifiers = $request['modifiers'];
		} else {
			$modifiers = array();

			if ( isset( $request['flip']['horizontal'] ) || isset( $request['flip']['vertical'] ) ) {
				$flip_args = array(
					'vertical'   => isset( $request['flip']['vertical'] ) ? (bool) $request['flip']['vertical'] : false,
					'horizontal' => isset( $request['flip']['horizontal'] ) ? (bool) $request['flip']['horizontal'] : false,
				);

				$modifiers[] = array(
					'type' => 'flip',
					'args' => array(
						'flip' => $flip_args,
					),
				);
			}

			if ( ! empty( $request['rotation'] ) ) {
				$modifiers[] = array(
					'type' => 'rotate',
					'args' => array(
						'angle' => $request['rotation'],
					),
				);
			}

			if ( isset( $request['x'], $request['y'], $request['width'], $request['height'] ) ) {
				$modifiers[] = array(
					'type' => 'crop',
					'args' => array(
						'left'   => $request['x'],
						'top'    => $request['y'],
						'width'  => $request['width'],
						'height' => $request['height'],
					),
				);
			}

			if ( 0 === count( $modifiers ) ) {
				return new WP_Error(
					'rest_image_not_edited',
					__( 'The image was not edited. Edit the image before applying the changes.' ),
					array( 'status' => 400 )
				);
			}
		}

		/*
		 * If the file doesn't exist, attempt a URL fopen on the src link.
		 * This can occur with certain file replication plugins.
		 * Keep the original file path to get a modified name later.
		 */
		$image_file_to_edit = $image_file;
		if ( ! file_exists( $image_file_to_edit ) ) {
			$image_file_to_edit = _load_image_to_edit_path( $attachment_id );
		}

		$image_editor = wp_get_image_editor( $image_file_to_edit );

		if ( is_wp_error( $image_editor ) ) {
			return new WP_Error(
				'rest_unknown_image_file_type',
				__( 'Unable to edit this image.' ),
				array( 'status' => 500 )
			);
		}

		// Apply any unapplied EXIF orientation so edits run in the upright frame the client previewed.
		$image_editor->maybe_exif_rotate();

		foreach ( $modifiers as $modifier ) {
			$args = $modifier['args'];
			switch ( $modifier['type'] ) {
				case 'flip':
					/*
					 * Flips the current image.
					 * The vertical flip is the first argument (flip along horizontal axis), the horizontal flip is the second argument (flip along vertical axis).
					 * See: WP_Image_Editor::flip()
					 */
					$result = $image_editor->flip( $args['flip']['vertical'], $args['flip']['horizontal'] );
					if ( is_wp_error( $result ) ) {
						return new WP_Error(
							'rest_image_flip_failed',
							__( 'Unable to flip this image.' ),
							array( 'status' => 500 )
						);
					}
					break;
				case 'rotate':
					// Rotation direction: clockwise vs. counterclockwise.
					$rotate = 0 - $args['angle'];

					if ( 0 !== $rotate ) {
						$result = $image_editor->rotate( $rotate );

						if ( is_wp_error( $result ) ) {
							return new WP_Error(
								'rest_image_rotation_failed',
								__( 'Unable to rotate this image.' ),
								array( 'status' => 500 )
							);
						}
					}

					break;

				case 'crop':
					$size = $image_editor->get_size();

					$crop_x = (int) round( ( $size['width'] * $args['left'] ) / 100.0 );
					$crop_y = (int) round( ( $size['height'] * $args['top'] ) / 100.0 );
					$width  = (int) round( ( $size['width'] * $args['width'] ) / 100.0 );
					$height = (int) round( ( $size['height'] * $args['height'] ) / 100.0 );

					if ( $size['width'] !== $width || $size['height'] !== $height ) {
						$result = $image_editor->crop( $crop_x, $crop_y, $width, $height );

						if ( is_wp_error( $result ) ) {
							return new WP_Error(
								'rest_image_crop_failed',
								__( 'Unable to crop this image.' ),
								array( 'status' => 500 )
							);
						}
					}

					break;

			}
		}

		// Calculate the file name.
		$image_ext  = pathinfo( $image_file, PATHINFO_EXTENSION );
		$image_name = wp_basename( $image_file, ".{$image_ext}" );

		/*
		 * Do not append multiple `-edited` to the file name.
		 * The user may be editing a previously edited image.
		 */
		if ( preg_match( '/-edited(-\d+)?$/', $image_name ) ) {
			// Remove any `-1`, `-2`, etc. `wp_unique_filename()` will add the proper number.
			$image_name = preg_replace( '/-edited(-\d+)?$/', '-edited', $image_name );
		} else {
			// Append `-edited` before the extension.
			$image_name .= '-edited';
		}

		$filename = "{$image_name}.{$image_ext}";

		// Create the uploads subdirectory if needed.
		$uploads = wp_upload_dir();

		// Make the file name unique in the (new) upload directory.
		$filename = wp_unique_filename( $uploads['path'], $filename );

		// Save to disk.
		$saved = $image_editor->save( $uploads['path'] . "/$filename" );

		if ( is_wp_error( $saved ) ) {
			return $saved;
		}

		// Grab original attachment post so we can use it to set defaults.
		$original_attachment_post = get_post( $attachment_id );

		// Check request fields and assign default values.
		$new_attachment_post                 = $this->prepare_item_for_database( $request );
		$new_attachment_post->post_mime_type = $saved['mime-type'];
		$new_attachment_post->guid           = $uploads['url'] . "/$filename";

		// Unset ID so wp_insert_attachment generates a new ID.
		unset( $new_attachment_post->ID );

		// Set new attachment post title with fallbacks.
		$new_attachment_post->post_title = $new_attachment_post->post_title ?? $original_attachment_post->post_title ?? $image_name;

		// Set new attachment post caption (post_excerpt).
		$new_attachment_post->post_excerpt = $new_attachment_post->post_excerpt ?? $original_attachment_post->post_excerpt ?? '';

		// Set new attachment post description (post_content) with fallbacks.
		$new_attachment_post->post_content = $new_attachment_post->post_content ?? $original_attachment_post->post_content ?? '';

		// Set post parent if set in request, else the default of `0` (no parent).
		$new_attachment_post->post_parent = $new_attachment_post->post_parent ?? 0;

		// Insert the new attachment post.
		$new_attachment_id = wp_insert_attachment( wp_slash( (array) $new_attachment_post ), $saved['path'], 0, true );

		if ( is_wp_error( $new_attachment_id ) ) {
			if ( 'db_update_error' === $new_attachment_id->get_error_code() ) {
				$new_attachment_id->add_data( array( 'status' => 500 ) );
			} else {
				$new_attachment_id->add_data( array( 'status' => 400 ) );
			}

			return $new_attachment_id;
		}

		// First, try to use the alt text from the request. If not set, copy the image alt text from the original attachment.
		$image_alt = isset( $request['alt_text'] ) ? sanitize_text_field( $request['alt_text'] ) : get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

		if ( ! empty( $image_alt ) ) {
			// update_post_meta() expects slashed.
			update_post_meta( $new_attachment_id, '_wp_attachment_image_alt', wp_slash( $image_alt ) );
		}

		if ( wp_is_serving_rest_request() ) {
			/*
			 * Set a custom header with the attachment_id.
			 * Used by the browser/client to resume creating image sub-sizes after a PHP fatal error.
			 */
			header( 'X-WP-Upload-Attachment-ID: ' . $new_attachment_id );
		}

		// Generate image sub-sizes and meta.
		$new_image_meta = wp_generate_attachment_metadata( $new_attachment_id, $saved['path'] );

		// Copy the EXIF metadata from the original attachment if not generated for the edited image.
		if ( isset( $image_meta['image_meta'] ) && isset( $new_image_meta['image_meta'] ) && is_array( $new_image_meta['image_meta'] ) ) {
			// Merge but skip empty values.
			foreach ( (array) $image_meta['image_meta'] as $key => $value ) {
				if ( empty( $new_image_meta['image_meta'][ $key ] ) && ! empty( $value ) ) {
					$new_image_meta['image_meta'][ $key ] = $value;
				}
			}
		}

		// Reset orientation. At this point the image is edited and orientation is correct.
		if ( ! empty( $new_image_meta['image_meta']['orientation'] ) ) {
			$new_image_meta['image_meta']['orientation'] = 1;
		}

		// The attachment_id may change if the site is exported and imported.
		$new_image_meta['parent_image'] = array(
			'attachment_id' => $attachment_id,
			// Path to the originally uploaded image file relative to the uploads directory.
			'file'          => _wp_relative_upload_path( $image_file ),
		);

		/**
		 * Filters the meta data for the new image created by editing an existing image.
		 *
		 * @since 5.5.0
		 *
		 * @param array $new_image_meta    Meta data for the new image.
		 * @param int   $new_attachment_id Attachment post ID for the new image.
		 * @param int   $attachment_id     Attachment post ID for the edited (parent) image.
		 */
		$new_image_meta = apply_filters( 'wp_edited_image_metadata', $new_image_meta, $new_attachment_id, $attachment_id );

		wp_update_attachment_metadata( $new_attachment_id, $new_image_meta );

		$response = $this->prepare_item_for_response( get_post( $new_attachment_id ), $request );
		$response->set_status( 201 );
		$response->header( 'Location', rest_url( sprintf( '%s/%s/%s', $this->namespace, $this->rest_base, $new_attachment_id ) ) );

		return $response;
	}

	/**
	 * Prepares a single attachment for create or update.
	 *
	 * @since 4.7.0
	 *
	 * @param WP_REST_Request $request Request object.
	 * @return stdClass|WP_Error Post object.
	 */
	protected function prepare_item_for_database( $request ) {
		$prepared_attachment = parent::prepare_item_for_database( $request );

		// Attachment caption (post_excerpt internally).
		if ( isset( $request['caption'] ) ) {
			if ( is_string( $request['caption'] ) ) {
				$prepared_attachment->post_excerpt = $request['caption'];
			} elseif ( isset( $request['caption']['raw'] ) ) {
				$prepared_attachment->post_excerpt = $request['caption']['raw'];
			}
		}

		// Attachment description (post_content internally).
		if ( isset( $request['description'] ) ) {
			if ( is_string( $request['description'] ) ) {
				$prepared_attachment->post_content = $request['description'];
			} elseif ( isset( $request['description']['raw'] ) ) {
				$prepared_attachment->post_content = $request['description']['raw'];
			}
		}

		if ( isset( $request['post'] ) ) {
			$prepared_attachment->post_parent = (int) $request['post'];
		}

		return $prepared_attachment;
	}

	/**
	 * Prepares a single attachment output for response.
	 *
	 * @since 4.7.0
	 * @since 5.9.0 Renamed `$post` to `$item` to match parent class for PHP 8 named parameter support.
	 *
	 * @param WP_Post         $item    Attachment object.
	 * @param WP_REST_Request $request Request object.
	 * @return WP_REST_Response Response object.
	 */
	public function prepare_item_for_response( $item, $request ) {
		// Restores the more descriptive, specific name for use within this method.
		$post = $item;

		$response = parent::prepare_item_for_response( $post, $request );
		$fields   = $this->get_fields_for_response( $request );
		/** @var array<string, mixed> $data */
		$data = $response->get_data();

		if ( in_array( 'description', $fields, true ) ) {
			$data['description'] = array(
				'raw'      => $post->post_content,
				/** This filter is documented in wp-includes/post-template.php */
				'rendered' => apply_filters( 'the_content', $post->post_content ),
			);
		}

		if ( in_array( 'caption', $fields, true ) ) {
			/** This filter is documented in wp-includes/post-template.php */
			$caption = apply_filters( 'get_the_excerpt', $post->post_excerpt, $post );

			/** This filter is documented in wp-includes/post-template.php */
			$caption = apply_filters( 'the_excerpt', $caption );

			$data['caption'] = array(
				'raw'      => $post->post_excerpt,
				'rendered' => $caption,
			);
		}

		if ( in_array( 'alt_text', $fields, true ) ) {
			$data['alt_text'] = get_post_meta( $post->ID, '_wp_attachment_image_alt', true );
		}

		if ( in_array( 'media_type', $fields, true ) ) {
			$data['media_type'] = wp_attachment_is_image( $post->ID ) ? 'image' : 'file';
		}

		if ( in_array( 'mime_type', $fields, true ) ) {
			$data['mime_type'] = $post->post_mime_type;
		}

		if ( in_array( 'media_details', $fields, true ) ) {
			$data['media_details'] = wp_get_attachment_metadata( $post->ID );

			// Ensure empty details is an empty object.
			if ( empty( $data['media_details'] ) ) {
				$data['media_details'] = new stdClass();
			} elseif ( ! empty( $data['media_details']['sizes'] ) ) {

				foreach ( $data['media_details']['sizes'] as $size => &$size_data ) {

					if ( isset( $size_data['mime-type'] ) ) {
						$size_data['mime_type'] = $size_data['mime-type'];
						unset( $size_data['mime-type'] );
					}

					// Use the same method image_downsize() does.
					$image_src = wp_get_attachment_image_src( $post->ID, $size );
					if ( ! $image_src ) {
						continue;
					}

					$size_data['source_url'] = $image_src[0];
				}
				unset( $size_data );

				$full_src = wp_get_attachment_image_src( $post->ID, 'full' );

				if ( ! empty( $full_src ) ) {
					$data['media_details']['sizes']['full'] = array(
						'file'       => wp_basename( $full_src[0] ),
						'width'      => $full_src[1],
						'height'     => $full_src[2],
						'mime_type'  => $post->post_mime_type,
						'source_url' => $full_src[0],
					);
				}
			} else {
				$data['media_details']['sizes'] = new stdClass();
			}
		}

		if ( in_array( 'post', $fields, true ) ) {
			$data['post'] = ! empty( $post->post_parent ) ? (int) $post->post_parent : null;
		}

		if ( in_array( 'source_url', $fields, true ) ) {
			$data['source_url'] = wp_get_attachment_url( $post->ID );
		}

		if ( in_array( 'missing_image_sizes', $fields, true ) ) {
			require_once ABSPATH . 'wp-admin/includes/image.php';
			$data['missing_image_sizes'] = array_keys( wp_get_missing_image_subsizes( $post->ID ) );

			// Handle PDFs which don't use wp_get_missing_image_subsizes().
			if ( empty( $data['missing_image_sizes'] ) && 'application/pdf' === get_post_mime_type( $post ) ) {
				$metadata = wp_get_attachment_metadata( $post->ID, true );

				if ( ! is_array( $metadata ) ) {
					$metadata = array();
				}

				$metadata['sizes'] = $metadata['sizes'] ?? array();

				$fallback_sizes = array(
					'thumbnail',
					'medium',
					'large',
				);

				// The filter might have been added by ::create_item().
				remove_filter( 'fallback_intermediate_image_sizes', '__return_empty_array', 100 );

				/** This filter is documented in wp-admin/includes/image.php */
				$fallback_sizes = apply_filters( 'fallback_intermediate_image_sizes', $fallback_sizes, $metadata );

				$registered_sizes = wp_get_registered_image_subsizes();
				$merged_sizes     = array_keys( array_intersect_key( $registered_sizes, array_flip( $fallback_sizes ) ) );

				$data['missing_image_sizes'] = array_values( array_diff( $merged_sizes, array_keys( $metadata['sizes'] ) ) );
			}
		}

		if ( in_array( 'filename', $fields, true ) ) {
			$data['filename'] = $this->get_attachment_filename( $post->ID );
		}

		if ( in_array( 'filesize', $fields, true ) ) {
			$data['filesize'] = $this->get_attachment_filesize( $post->ID );
		}

		if ( in_array( 'exif_orientation', $fields, true ) && wp_attachment_is_image( $post ) ) {
			$metadata = wp_get_attachment_metadata( $post->ID, true );

			// Default to 1 (no rotation needed) if orientation not set.
			$orientation = 1;

			if (
				is_array( $metadata ) &&
				isset( $metadata['image_meta']['orientation'] ) &&
				(int) $metadata['image_meta']['orientation'] > 0
			) {
				$orientation = (int) $metadata['image_meta']['orientation'];
			}

			$data['exif_orientation'] = $orientation;
		}

		if ( wp_attachment_is_image( $post ) ) {
			$mime_type = (string) get_post_mime_type( $post );

			/*
			 * Per-file output format for images, evaluated with the real filename
			 * and MIME type so plugins filtering image_editor_output_format can
			 * make per-attachment decisions (e.g. JPEG -> WebP). Resolved the same
			 * way WP_Image_Editor::set_quality() resolves the output format.
			 */
			if ( in_array( 'image_output_format', $fields, true ) ) {
				$filename = get_attached_file( $post->ID );

				/** This filter is documented in wp-includes/media.php */
				$output_formats = apply_filters(
					'image_editor_output_format',
					array( $mime_type => $mime_type ),
					$filename ? $filename : '',
					$mime_type
				);

				$output_mime                 = $output_formats[ $mime_type ] ?? $mime_type;
				$data['image_output_format'] = ( $output_mime !== $mime_type ) ? $output_mime : null;
			}

			/*
			 * Per-file progressive/interlaced encoding flag for images, evaluated
			 * against the attachment's MIME type.
			 */
			if ( in_array( 'image_save_progressive', $fields, true ) ) {
				/** This filter is documented in wp-includes/class-wp-image-editor-gd.php */
				$data['image_save_progressive'] = (bool) apply_filters( 'image_save_progressive', false, $mime_type );
			}

			if ( in_array( 'image_quality', $fields, true ) ) {
				$filename = get_attached_file( $post->ID );

				/** This filter is documented in wp-includes/media.php */
				$output_formats = apply_filters(
					'image_editor_output_format',
					array( $mime_type => $mime_type ),
					$filename ? $filename : '',
					$mime_type
				);
				$output_mime    = $output_formats[ $mime_type ] ?? $mime_type;

				$metadata    = wp_get_attachment_metadata( $post->ID, true );
				$full_width  = max( 0, ( is_array( $metadata ) && isset( $metadata['width'] ) ) ? (int) $metadata['width'] : 0 );
				$full_height = max( 0, ( is_array( $metadata ) && isset( $metadata['height'] ) ) ? (int) $metadata['height'] : 0 );

				$full_quality = wp_get_image_encode_quality(
					$output_mime,
					array(
						'width'  => $full_width,
						'height' => $full_height,
					)
				);

				$size_quality = array();

				foreach ( wp_get_registered_image_subsizes() as $size_name => $size_data ) {
					$quality = wp_get_image_encode_quality(
						$output_mime,
						array(
							'width'  => (int) $size_data['width'],
							'height' => (int) $size_data['height'],
						)
					);

					// Only report sizes whose quality diverges from the full-size value.
					if ( $quality !== $full_quality ) {
						$size_quality[ $size_name ] = $quality;
					}
				}

				$data['image_quality'] = array(
					'default' => $full_quality,
					'sizes'   => $size_quality,
				);
			}
		}

		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';

		$data = $this->filter_response_by_context( $data, $context );

		$links = $response->get_links();

		// Wrap the data in a response object.
		$response = rest_ensure_response( $data );

		foreach ( $links as $rel => $rel_links ) {
			foreach ( $rel_links as $link ) {
				$response->add_link( $rel, $link['href'], $link['attributes'] );
			}
		}

		/**
		 * Filters an attachment returned from the REST API.
		 *
		 * Allows modification of the attachment right before it is returned.
		 *
		 * @since 4.7.0
		 *
		 * @param WP_REST_Response $response The response object.
		 * @param WP_Post          $post     The original attachment post.
		 * @param WP_REST_Request  $request  Request used to generate the response.
		 */
		return apply_filters( 'rest_prepare_attachment', $response, $post, $request );
	}

	/**
	 * Prepares attachment links for the request.
	 *
	 * @since 6.9.0
	 *
	 * @param WP_Post $post Post object.
	 * @return array Links for the given attachment.
	 */
	protected function prepare_links( $post ) {
		$links = parent::prepare_links( $post );

		if ( ! empty( $post->post_parent ) ) {
			$post = get_post( $post->post_parent );

			if ( ! empty( $post ) ) {
				$links['https://api.w.org/attached-to'] = array(
					'href'       => rest_url( rest_get_route_for_post( $post ) ),
					'embeddable' => true,
					'post_type'  => $post->post_type,
					'id'         => $post->ID,
				);
			}
		}

		return $links;
	}

	/**
	 * Retrieves the attachment's schema, conforming to JSON Schema.
	 *
	 * @since 4.7.0
	 *
	 * @return array Item schema as an array.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$schema = parent::get_item_schema();

		$schema['properties']['alt_text'] = array(
			'description' => __( 'Alternative text to display when attachment is not displayed.' ),
			'type'        => 'string',
			'context'     => array( 'view', 'edit', 'embed' ),
			'arg_options' => array(
				'sanitize_callback' => 'sanitize_text_field',
			),
		);

		$schema['properties']['caption'] = array(
			'description' => __( 'The attachment caption.' ),
			'type'        => 'object',
			'context'     => array( 'view', 'edit', 'embed' ),
			'arg_options' => array(
				'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database().
				'validate_callback' => null, // Note: validation implemented in self::prepare_item_for_database().
			),
			'properties'  => array(
				'raw'      => array(
					'description' => __( 'Caption for the attachment, as it exists in the database.' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
				),
				'rendered' => array(
					'description' => __( 'HTML caption for the attachment, transformed for display.' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit', 'embed' ),
					'readonly'    => true,
				),
			),
		);

		$schema['properties']['description'] = array(
			'description' => __( 'The attachment description.' ),
			'type'        => 'object',
			'context'     => array( 'view', 'edit' ),
			'arg_options' => array(
				'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database().
				'validate_callback' => null, // Note: validation implemented in self::prepare_item_for_database().
			),
			'properties'  => array(
				'raw'      => array(
					'description' => __( 'Description for the attachment, as it exists in the database.' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
				),
				'rendered' => array(
					'description' => __( 'HTML description for the attachment, transformed for display.' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
			),
		);

		$schema['properties']['media_type'] = array(
			'description' => __( 'Attachment type.' ),
			'type'        => 'string',
			'enum'        => array( 'image', 'file' ),
			'context'     => array( 'view', 'edit', 'embed' ),
			'readonly'    => true,
		);

		$schema['properties']['mime_type'] = array(
			'description' => __( 'The attachment MIME type.' ),
			'type'        => 'string',
			'context'     => array( 'view', 'edit', 'embed' ),
			'readonly'    => true,
		);

		$schema['properties']['media_details'] = array(
			'description' => __( 'Details about the media file, specific to its type.' ),
			'type'        => 'object',
			'context'     => array( 'view', 'edit', 'embed' ),
			'readonly'    => true,
		);

		$schema['properties']['post'] = array(
			'description' => __( 'The ID for the associated post of the attachment.' ),
			'type'        => 'integer',
			'context'     => array( 'view', 'edit' ),
		);

		$schema['properties']['source_url'] = array(
			'description' => __( 'URL to the original attachment file.' ),
			'type'        => 'string',
			'format'      => 'uri',
			'context'     => array( 'view', 'edit', 'embed' ),
			'readonly'    => true,
		);

		$schema['properties']['missing_image_sizes'] = array(
			'description' => __( 'List of the missing image sizes of the attachment.' ),
			'type'        => 'array',
			'items'       => array( 'type' => 'string' ),
			'context'     => array( 'edit' ),
			'readonly'    => true,
		);

		$schema['properties']['filename'] = array(
			'description' => __( 'Original attachment file name.' ),
			'type'        => 'string',
			'context'     => array( 'view', 'edit' ),
			'readonly'    => true,
		);

		$schema['properties']['filesize'] = array(
			'description' => __( 'Attachment file size in bytes.' ),
			'type'        => array( 'integer', 'null' ),
			'context'     => array( 'view', 'edit' ),
			'readonly'    => true,
		);

		$schema['properties']['exif_orientation'] = array(
			'description' => __( 'EXIF orientation value. Values 1-8 follow the EXIF specification, where 1 means no rotation needed.' ),
			'type'        => 'integer',
			'context'     => array( 'edit' ),
			'readonly'    => true,
		);

		// Enumerate the registered sub-sizes so the schema documents exactly which
		// keys may appear under "sizes".
		$size_quality_properties = array();
		foreach ( array_keys( wp_get_registered_image_subsizes() ) as $size_name ) {
			$size_quality_properties[ $size_name ] = array(
				'type'    => 'integer',
				'minimum' => 1,
				'maximum' => 100,
			);
		}

		$schema['properties']['image_quality'] = array(
			'description' => __( 'Encode quality (1-100) from the wp_editor_set_quality filter, resolved against the output MIME type. The "default" value applies to the full-size image; "sizes" lists per-registered-size overrides where the filtered value differs from "default".' ),
			'type'        => 'object',
			'context'     => array( 'edit' ),
			'readonly'    => true,
			'properties'  => array(
				'default' => array(
					'type'    => 'integer',
					'minimum' => 1,
					'maximum' => 100,
				),
				'sizes'   => array(
					'type'       => 'object',
					'properties' => $size_quality_properties,
				),
			),
		);

		$schema['properties']['image_output_format'] = array(
			'description' => __( 'The output MIME type this image should be converted to, based on the image_editor_output_format filter. Null if no conversion is needed.' ),
			'type'        => array( 'string', 'null' ),
			'context'     => array( 'edit' ),
			'readonly'    => true,
		);

		$schema['properties']['image_save_progressive'] = array(
			'description' => __( 'Whether to use progressive/interlaced encoding when saving this image.' ),
			'type'        => 'boolean',
			'context'     => array( 'edit' ),
			'readonly'    => true,
		);

		unset( $schema['properties']['password'] );

		$this->schema = $schema;

		return $this->add_additional_fields_schema( $this->schema );
	}

	/**
	 * Handles an upload via raw POST data.
	 *
	 * @since 4.7.0
	 * @since 6.6.0 Added the `$time` parameter.
	 *
	 * @param string      $data    Supplied file data.
	 * @param array       $headers HTTP headers from the request.
	 * @param string|null $time    Optional. Time formatted in 'yyyy/mm'. Default null.
	 * @return array{ file: non-empty-string, url: non-empty-string, type: non-empty-string }|WP_Error Data from wp_handle_sideload().
	 */
	protected function upload_from_data( $data, $headers, $time = null ) {
		if ( empty( $data ) ) {
			return new WP_Error(
				'rest_upload_no_data',
				__( 'No data supplied.' ),
				array( 'status' => 400 )
			);
		}

		if ( empty( $headers['content_type'] ) ) {
			return new WP_Error(
				'rest_upload_no_content_type',
				__( 'No Content-Type supplied.' ),
				array( 'status' => 400 )
			);
		}

		if ( empty( $headers['content_disposition'] ) ) {
			return new WP_Error(
				'rest_upload_no_content_disposition',
				__( 'No Content-Disposition supplied.' ),
				array( 'status' => 400 )
			);
		}

		$filename = self::get_filename_from_disposition( $headers['content_disposition'] );

		if ( empty( $filename ) ) {
			return new WP_Error(
				'rest_upload_invalid_disposition',
				__( 'Invalid Content-Disposition supplied. Content-Disposition needs to be formatted as `attachment; filename="image.png"` or similar.' ),
				array( 'status' => 400 )
			);
		}

		if ( ! empty( $headers['content_md5'] ) ) {
			$content_md5 = array_shift( $headers['content_md5'] );
			$expected    = trim( $content_md5 );
			$actual      = md5( $data );

			if ( $expected !== $actual ) {
				return new WP_Error(
					'rest_upload_hash_mismatch',
					__( 'Content hash did not match expected.' ),
					array( 'status' => 412 )
				);
			}
		}

		// Get the content-type.
		$type = array_shift( $headers['content_type'] );

		// Include filesystem functions to get access to wp_tempnam() and wp_handle_sideload().
		require_once ABSPATH . 'wp-admin/includes/file.php';

		// Save the file.
		$tmpfname = wp_tempnam( $filename );

		$fp = fopen( $tmpfname, 'w+' );

		if ( ! $fp ) {
			return new WP_Error(
				'rest_upload_file_error',
				__( 'Could not open file handle.' ),
				array( 'status' => 500 )
			);
		}

		fwrite( $fp, $data );
		fclose( $fp );

		// Now, sideload it in.
		$file_data = array(
			'error'    => null,
			'tmp_name' => $tmpfname,
			'name'     => $filename,
			'type'     => $type,
		);

		$size_check = self::check_upload_size( $file_data );
		if ( is_wp_error( $size_check ) ) {
			return $size_check;
		}

		$overrides = array(
			'test_form' => false,
		);

		$sideloaded = wp_handle_sideload( $file_data, $overrides, $time );

		if ( isset( $sideloaded['error'] ) ) {
			@unlink( $tmpfname );

			return new WP_Error(
				'rest_upload_sideload_error',
				$sideloaded['error'],
				array( 'status' => 500 )
			);
		}

		return $sideloaded;
	}

	/**
	 * Parses filename from a Content-Disposition header value.
	 *
	 * As per RFC6266:
	 *
	 *     content-disposition = "Content-Disposition" ":"
	 *                            disposition-type *( ";" disposition-parm )
	 *
	 *     disposition-type    = "inline" | "attachment" | disp-ext-type
	 *                         ; case-insensitive
	 *     disp-ext-type       = token
	 *
	 *     disposition-parm    = filename-parm | disp-ext-parm
	 *
	 *     filename-parm       = "filename" "=" value
	 *                         | "filename*" "=" ext-value
	 *
	 *     disp-ext-parm       = token "=" value
	 *                         | ext-token "=" ext-value
	 *     ext-token           = <the characters in token, followed by "*">
	 *
	 * @since 4.7.0
	 *
	 * @link https://tools.ietf.org/html/rfc2388
	 * @link https://tools.ietf.org/html/rfc6266
	 *
	 * @param string[] $disposition_header List of Content-Disposition header values.
	 * @return string|null Filename if available, or null if not found.
	 */
	public static function get_filename_from_disposition( $disposition_header ) {
		// Get the filename.
		$filename = null;

		foreach ( $disposition_header as $value ) {
			$value = trim( $value );

			if ( ! str_contains( $value, ';' ) ) {
				continue;
			}

			list( , $attr_parts ) = explode( ';', $value, 2 );

			$attr_parts = explode( ';', $attr_parts );
			$attributes = array();

			foreach ( $attr_parts as $part ) {
				if ( ! str_contains( $part, '=' ) ) {
					continue;
				}

				list( $key, $value ) = explode( '=', $part, 2 );

				$attributes[ trim( $key ) ] = trim( $value );
			}

			if ( empty( $attributes['filename'] ) ) {
				continue;
			}

			$filename = trim( $attributes['filename'] );

			// Unquote quoted filename, but after trimming.
			if ( str_starts_with( $filename, '"' ) && str_ends_with( $filename, '"' ) ) {
				$filename = substr( $filename, 1, -1 );
			}
		}

		return $filename;
	}

	/**
	 * Retrieves the query params for collections of attachments.
	 *
	 * @since 4.7.0
	 * @since 6.9.0 Extends the `media_type` and `mime_type` request arguments to support array values.
	 *
	 * @return array Query parameters for the attachment collection as an array.
	 */
	public function get_collection_params() {
		$params                            = parent::get_collection_params();
		$params['status']['default']       = 'inherit';
		$params['status']['items']['enum'] = array( 'inherit', 'private', 'trash' );
		$media_types                       = array_keys( $this->get_media_types() );

		$params['media_type'] = array(
			'default'     => null,
			'description' => __( 'Limit result set to attachments of a particular media type or media types.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'string',
				'enum' => $media_types,
			),
		);

		$params['mime_type'] = array(
			'default'     => null,
			'description' => __( 'Limit result set to attachments of a particular MIME type or MIME types.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'string',
			),
		);

		return $params;
	}

	/**
	 * Handles an upload via multipart/form-data ($_FILES).
	 *
	 * @since 4.7.0
	 * @since 6.6.0 Added the `$time` parameter.
	 *
	 * @param array       $files   Data from the `$_FILES` superglobal.
	 * @param array       $headers HTTP headers from the request.
	 * @param string|null $time    Optional. Time formatted in 'yyyy/mm'. Default null.
	 * @return array{ file: non-empty-string, url: non-empty-string, type: non-empty-string }|WP_Error Data from wp_handle_upload().
	 */
	protected function upload_from_file( $files, $headers, $time = null ) {
		if ( empty( $files ) ) {
			return new WP_Error(
				'rest_upload_no_data',
				__( 'No data supplied.' ),
				array( 'status' => 400 )
			);
		}

		// Verify hash, if given.
		if ( ! empty( $headers['content_md5'] ) ) {
			$content_md5 = array_shift( $headers['content_md5'] );
			$expected    = trim( $content_md5 );
			$actual      = md5_file( $files['file']['tmp_name'] );

			if ( $expected !== $actual ) {
				return new WP_Error(
					'rest_upload_hash_mismatch',
					__( 'Content hash did not match expected.' ),
					array( 'status' => 412 )
				);
			}
		}

		// Pass off to WP to handle the actual upload.
		$overrides = array(
			'test_form' => false,
		);

		// Bypasses is_uploaded_file() when running unit tests.
		if ( defined( 'DIR_TESTDATA' ) && DIR_TESTDATA ) {
			$overrides['action'] = 'wp_handle_mock_upload';
		}

		$size_check = self::check_upload_size( $files['file'] );
		if ( is_wp_error( $size_check ) ) {
			return $size_check;
		}

		// Include filesystem functions to get access to wp_handle_upload().
		require_once ABSPATH . 'wp-admin/includes/file.php';

		$file = wp_handle_upload( $files['file'], $overrides, $time );

		if ( isset( $file['error'] ) ) {
			return new WP_Error(
				'rest_upload_unknown_error',
				$file['error'],
				array( 'status' => 500 )
			);
		}

		return $file;
	}

	/**
	 * Retrieves the supported media types.
	 *
	 * Media types are considered the MIME type category.
	 *
	 * @since 4.7.0
	 *
	 * @return array Array of supported media types.
	 */
	protected function get_media_types() {
		$media_types = array();

		foreach ( get_allowed_mime_types() as $mime_type ) {
			$parts = explode( '/', $mime_type );

			if ( ! isset( $media_types[ $parts[0] ] ) ) {
				$media_types[ $parts[0] ] = array();
			}

			$media_types[ $parts[0] ][] = $mime_type;
		}

		return $media_types;
	}

	/**
	 * Determine if uploaded file exceeds space quota on multisite.
	 *
	 * Replicates check_upload_size().
	 *
	 * @since 4.9.8
	 *
	 * @param array $file $_FILES array for a given file.
	 * @return true|WP_Error True if can upload, error for errors.
	 */
	protected function check_upload_size( $file ) {
		if ( ! is_multisite() ) {
			return true;
		}

		if ( get_site_option( 'upload_space_check_disabled' ) ) {
			return true;
		}

		$space_left = get_upload_space_available();

		$file_size = filesize( $file['tmp_name'] );

		if ( $space_left < $file_size ) {
			return new WP_Error(
				'rest_upload_limited_space',
				/* translators: %s: Required disk space in kilobytes. */
				sprintf( __( 'Not enough space to upload. %s KB needed.' ), number_format( ( $file_size - $space_left ) / KB_IN_BYTES ) ),
				array( 'status' => 400 )
			);
		}

		if ( $file_size > ( KB_IN_BYTES * get_site_option( 'fileupload_maxk', 1500 ) ) ) {
			return new WP_Error(
				'rest_upload_file_too_big',
				/* translators: %s: Maximum allowed file size in kilobytes. */
				sprintf( __( 'This file is too big. Files must be less than %s KB in size.' ), get_site_option( 'fileupload_maxk', 1500 ) ),
				array( 'status' => 400 )
			);
		}

		// Include multisite admin functions to get access to upload_is_user_over_quota().
		require_once ABSPATH . 'wp-admin/includes/ms.php';

		if ( upload_is_user_over_quota( false ) ) {
			return new WP_Error(
				'rest_upload_user_quota_exceeded',
				__( 'You have used your space quota. Please delete files before uploading.' ),
				array( 'status' => 400 )
			);
		}

		return true;
	}

	/**
	 * Gets the request args for the edit item route.
	 *
	 * @since 5.5.0
	 * @since 6.9.0 Adds flips capability and editable fields for the newly-created attachment post.
	 *
	 * @return array
	 */
	protected function get_edit_media_item_args() {
		$args = array(
			'src'       => array(
				'description' => __( 'URL to the edited image file.' ),
				'type'        => 'string',
				'format'      => 'uri',
				'required'    => true,
			),
			// The `modifiers` param takes precedence over the older format.
			'modifiers' => array(
				'description' => __( 'Array of image edits.' ),
				'type'        => 'array',
				'minItems'    => 1,
				'items'       => array(
					'description' => __( 'Image edit.' ),
					'type'        => 'object',
					'required'    => array(
						'type',
						'args',
					),
					'oneOf'       => array(
						array(
							'title'      => __( 'Flip' ),
							'properties' => array(
								'type' => array(
									'description' => __( 'Flip type.' ),
									'type'        => 'string',
									'enum'        => array( 'flip' ),
								),
								'args' => array(
									'description' => __( 'Flip arguments.' ),
									'type'        => 'object',
									'required'    => array(
										'flip',
									),
									'properties'  => array(
										'flip' => array(
											'description' => __( 'Flip direction.' ),
											'type'        => 'object',
											'required'    => array(
												'horizontal',
												'vertical',
											),
											'properties'  => array(
												'horizontal' => array(
													'description' => __( 'Whether to flip in the horizontal direction.' ),
													'type' => 'boolean',
												),
												'vertical' => array(
													'description' => __( 'Whether to flip in the vertical direction.' ),
													'type' => 'boolean',
												),
											),
										),
									),
								),
							),
						),
						array(
							'title'      => __( 'Rotation' ),
							'properties' => array(
								'type' => array(
									'description' => __( 'Rotation type.' ),
									'type'        => 'string',
									'enum'        => array( 'rotate' ),
								),
								'args' => array(
									'description' => __( 'Rotation arguments.' ),
									'type'        => 'object',
									'required'    => array(
										'angle',
									),
									'properties'  => array(
										'angle' => array(
											'description' => __( 'Angle to rotate clockwise in degrees.' ),
											'type'        => 'number',
										),
									),
								),
							),
						),
						array(
							'title'      => __( 'Crop' ),
							'properties' => array(
								'type' => array(
									'description' => __( 'Crop type.' ),
									'type'        => 'string',
									'enum'        => array( 'crop' ),
								),
								'args' => array(
									'description' => __( 'Crop arguments.' ),
									'type'        => 'object',
									'required'    => array(
										'left',
										'top',
										'width',
										'height',
									),
									'properties'  => array(
										'left'   => array(
											'description' => __( 'Horizontal position from the left to begin the crop as a percentage of the image width.' ),
											'type'        => 'number',
										),
										'top'    => array(
											'description' => __( 'Vertical position from the top to begin the crop as a percentage of the image height.' ),
											'type'        => 'number',
										),
										'width'  => array(
											'description' => __( 'Width of the crop as a percentage of the image width.' ),
											'type'        => 'number',
										),
										'height' => array(
											'description' => __( 'Height of the crop as a percentage of the image height.' ),
											'type'        => 'number',
										),
									),
								),
							),
						),
					),
				),
			),
			'rotation'  => array(
				'description'      => __( 'The amount to rotate the image clockwise in degrees. DEPRECATED: Use `modifiers` instead.' ),
				'type'             => 'integer',
				'minimum'          => 0,
				'exclusiveMinimum' => true,
				'maximum'          => 360,
				'exclusiveMaximum' => true,
			),
			'x'         => array(
				'description' => __( 'As a percentage of the image, the x position to start the crop from. DEPRECATED: Use `modifiers` instead.' ),
				'type'        => 'number',
				'minimum'     => 0,
				'maximum'     => 100,
			),
			'y'         => array(
				'description' => __( 'As a percentage of the image, the y position to start the crop from. DEPRECATED: Use `modifiers` instead.' ),
				'type'        => 'number',
				'minimum'     => 0,
				'maximum'     => 100,
			),
			'width'     => array(
				'description' => __( 'As a percentage of the image, the width to crop the image to. DEPRECATED: Use `modifiers` instead.' ),
				'type'        => 'number',
				'minimum'     => 0,
				'maximum'     => 100,
			),
			'height'    => array(
				'description' => __( 'As a percentage of the image, the height to crop the image to. DEPRECATED: Use `modifiers` instead.' ),
				'type'        => 'number',
				'minimum'     => 0,
				'maximum'     => 100,
			),
		);

		/*
		 * Get the args based on the post schema. This calls `rest_get_endpoint_args_for_schema()`,
		 * which also takes care of sanitization and validation.
		 */
		$update_item_args = $this->get_endpoint_args_for_item_schema( WP_REST_Server::EDITABLE );

		if ( isset( $update_item_args['caption'] ) ) {
			$args['caption'] = $update_item_args['caption'];
		}

		if ( isset( $update_item_args['description'] ) ) {
			$args['description'] = $update_item_args['description'];
		}

		if ( isset( $update_item_args['title'] ) ) {
			$args['title'] = $update_item_args['title'];
		}

		if ( isset( $update_item_args['post'] ) ) {
			$args['post'] = $update_item_args['post'];
		}

		if ( isset( $update_item_args['alt_text'] ) ) {
			$args['alt_text'] = $update_item_args['alt_text'];
		}

		return $args;
	}

	/**
	 * Gets the attachment's original file name.
	 *
	 * @since 7.0.0
	 *
	 * @param int $attachment_id Attachment ID.
	 * @return string|null Attachment file name, or null if not found.
	 */
	protected function get_attachment_filename( int $attachment_id ): ?string {
		$path = wp_get_original_image_path( $attachment_id );

		if ( $path ) {
			return wp_basename( $path );
		}

		$path = get_attached_file( $attachment_id );

		if ( $path ) {
			return wp_basename( $path );
		}

		return null;
	}

	/**
	 * Gets the attachment's file size in bytes.
	 *
	 * @since 7.0.0
	 *
	 * @param int $attachment_id Attachment ID.
	 * @return int|null Attachment file size in bytes, or null if not available.
	 * @phpstan-return non-negative-int|null
	 */
	protected function get_attachment_filesize( int $attachment_id ): ?int {
		$meta = wp_get_attachment_metadata( $attachment_id );

		if ( isset( $meta['filesize'] ) && is_numeric( $meta['filesize'] ) && $meta['filesize'] > 0 ) {
			return (int) $meta['filesize'];
		}

		$original_path = wp_get_original_image_path( $attachment_id );
		$attached_file = $original_path ? $original_path : get_attached_file( $attachment_id );

		if ( is_string( $attached_file ) && is_readable( $attached_file ) ) {
			return wp_filesize( $attached_file );
		}

		return null;
	}

	/**
	 * Checks if a given request has access to sideload a file.
	 *
	 * Sideloading a file for an existing attachment
	 * requires both update and create permissions.
	 *
	 * @since 7.1.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True if the request has access to update the item, WP_Error object otherwise.
	 */
	public function sideload_item_permissions_check( $request ) {
		return $this->edit_media_item_permissions_check( $request );
	}

	/**
	 * Validates an image size name, or an array of names sharing a single file.
	 *
	 * Shared by the sideload endpoint, which names the size a file is produced
	 * for, and the finalize endpoint, which names the size each submitted entry
	 * is stored under. Both need the same set, and finalize accepts a payload of
	 * its own rather than one this class produced, so leaving it unconstrained
	 * there would let a submission write an arbitrary key into the metadata
	 * 'sizes' array or route a file into a branch it was never produced for.
	 *
	 * @since 7.1.0
	 *
	 * @param mixed  $value The image size name, or an array of names.
	 * @param string $param Parameter name, used in the error messages.
	 * @return true|WP_Error True when every name is valid, WP_Error otherwise.
	 */
	private static function validate_image_size_names( $value, string $param ) {
		$special_sizes = self::get_special_image_sizes();
		$regular_sizes = array_values(
			array_diff(
				array_merge(
					array_keys( wp_get_registered_image_subsizes() ),
					// Not a registered sub-size, but stored as an ordinary
					// entry in the metadata 'sizes' array (PDF thumbnails).
					array( 'full' )
				),
				$special_sizes
			)
		);

		if ( is_string( $value ) ) {
			$items       = array( $value );
			$valid_sizes = array_merge( $regular_sizes, $special_sizes );
		} elseif ( is_array( $value ) ) {
			/**
			 * An array registers one sideloaded file under several size names,
			 * which only makes sense for regular sub-sizes: each special size
			 * names a single file with its own handling in
			 * {@see self::sideload_item()} and its own metadata key in
			 * {@see self::finalize_item()}. Rejecting them here is what lets the
			 * array branches in both methods treat an array as regular sizes.
			 */
			$items       = $value;
			$valid_sizes = $regular_sizes;
		} else {
			return new WP_Error(
				'rest_invalid_type',
				/* translators: %s: Parameter name. */
				sprintf( __( '%s must be a string or an array of strings.' ), $param )
			);
		}

		foreach ( $items as $item ) {
			if ( ! in_array( $item, $valid_sizes, true ) ) {
				return new WP_Error(
					'rest_not_in_enum',
					/* translators: %s: Parameter name. */
					sprintf( __( '%s contains an invalid image size.' ), $param )
				);
			}
		}

		return true;
	}

	/**
	 * Returns the image size names which name a single file rather than a sub-size.
	 *
	 * Each of these is handled on its own in {@see self::sideload_item()} and stored
	 * under its own key by {@see self::finalize_item()}, so unlike a regular
	 * sub-size none of them may appear in an array of names sharing one file.
	 *
	 * @since 7.1.0
	 *
	 * @return string[] Special image size names.
	 *
	 * @phpstan-return non-empty-list<non-empty-string>
	 */
	private static function get_special_image_sizes(): array {
		return array(
			'original',
			'scaled',
			// Source-format original (e.g. the HEIC kept alongside its JPEG derivative).
			self::IMAGE_SIZE_SOURCE_ORIGINAL,
			// Converted-video companions for an animated GIF (the MP4/WebM and its poster).
			'animated_video',
			'animated_video_poster',
		);
	}

	/**
	 * Validates that uploaded image dimensions are appropriate for the specified image size.
	 *
	 * @since 7.1.0
	 *
	 * @param int    $width         Uploaded image width.
	 * @param int    $height        Uploaded image height.
	 * @param string $image_size    The target image size name.
	 * @param int    $attachment_id The attachment ID.
	 * @return true|WP_Error True if valid, WP_Error if invalid.
	 */
	private function validate_image_dimensions( int $width, int $height, string $image_size, int $attachment_id ) {
		// All image sizes require positive dimensions.
		if ( $width <= 0 || $height <= 0 ) {
			return new WP_Error(
				'rest_upload_invalid_dimensions',
				__( 'Uploaded image must have positive dimensions.' ),
				array( 'status' => 400 )
			);
		}

		/*
		 * 'original' size: the full-size image that replaces the main file (see
		 * sideload_item()/finalize_item()). The endpoint expects any EXIF
		 * orientation to be applied to the image already, which can swap width
		 * and height, so the dimensions must match the stored dimensions or be
		 * their transpose.
		 */
		if ( 'original' === $image_size ) {
			$metadata = wp_get_attachment_metadata( $attachment_id, true );
			if ( is_array( $metadata ) && isset( $metadata['width'], $metadata['height'] ) ) {
				$expected_width  = (int) $metadata['width'];
				$expected_height = (int) $metadata['height'];

				$matches_dimensions    = $width === $expected_width && $height === $expected_height;
				$transposes_dimensions = $width === $expected_height && $height === $expected_width;

				if ( ! $matches_dimensions && ! $transposes_dimensions ) {
					return new WP_Error(
						'rest_upload_dimension_mismatch',
						sprintf(
							/* translators: 1: Actual width, 2: actual height, 3: expected width, 4: expected height. */
							__( 'Uploaded image dimensions (%1$dx%2$d) do not match original image dimensions (%3$dx%4$d).' ),
							$width,
							$height,
							$expected_width,
							$expected_height
						),
						array( 'status' => 400 )
					);
				}
			}
			return true;
		}

		// 'full' size (PDF thumbnails) and 'scaled': no further constraints.
		if ( in_array( $image_size, array( 'full', 'scaled' ), true ) ) {
			return true;
		}

		/*
		 * 'animated_video_poster' companion: a static poster image for the
		 * converted video. It is a real image (so it has positive dimensions)
		 * but is not a registered sub-size, so it has no dimension constraint.
		 */
		if ( 'animated_video_poster' === $image_size ) {
			return true;
		}

		// Regular image sizes: validate against registered size constraints.
		$registered_sizes = wp_get_registered_image_subsizes();

		if ( ! isset( $registered_sizes[ $image_size ] ) ) {
			return new WP_Error(
				'rest_upload_unknown_size',
				__( 'Unknown image size.' ),
				array( 'status' => 400 )
			);
		}

		$size_data  = $registered_sizes[ $image_size ];
		$max_width  = (int) $size_data['width'];
		$max_height = (int) $size_data['height'];

		// Validate dimensions don't exceed the registered size maximums.
		// Allow 1px tolerance for rounding differences.
		$tolerance = 1;

		if ( $this->dimension_exceeds_max( $width, $max_width, $tolerance ) ) {
			return new WP_Error(
				'rest_upload_dimension_mismatch',
				sprintf(
					/* translators: 1: Image size name, 2: maximum width, 3: actual width. */
					__( 'Uploaded image width (%3$d) exceeds maximum for "%1$s" size (%2$d).' ),
					$image_size,
					$max_width,
					$width
				),
				array( 'status' => 400 )
			);
		}

		if ( $this->dimension_exceeds_max( $height, $max_height, $tolerance ) ) {
			return new WP_Error(
				'rest_upload_dimension_mismatch',
				sprintf(
					/* translators: 1: Image size name, 2: maximum height, 3: actual height. */
					__( 'Uploaded image height (%3$d) exceeds maximum for "%1$s" size (%2$d).' ),
					$image_size,
					$max_height,
					$height
				),
				array( 'status' => 400 )
			);
		}

		return true;
	}

	/**
	 * Checks whether a dimension exceeds the maximum allowed value.
	 *
	 * A maximum of zero means the dimension is unconstrained.
	 *
	 * @since 7.1.0
	 *
	 * @param int $value     The actual dimension in pixels.
	 * @param int $max       The maximum allowed dimension in pixels. Zero means no constraint.
	 * @param int $tolerance Pixel tolerance allowed for rounding differences.
	 * @return bool True if the value exceeds the maximum plus tolerance.
	 */
	private function dimension_exceeds_max( int $value, int $max, int $tolerance ): bool {
		return $max > 0 && $value > $max + $tolerance;
	}

	/**
	 * Side-loads a media file without creating a new attachment.
	 *
	 * @since 7.1.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function sideload_item( WP_REST_Request $request ) {
		$attachment_id = (int) $request['id'];

		$post = $this->get_post( $attachment_id );

		if ( is_wp_error( $post ) ) {
			return $post;
		}

		if (
			! wp_attachment_is_image( $post ) &&
			! wp_attachment_is( 'pdf', $post )
		) {
			return new WP_Error(
				'rest_post_invalid_id',
				__( 'Invalid post ID. Only images and PDFs can be sideloaded.' ),
				array( 'status' => 400 )
			);
		}

		/*
		 * Sideloaded files are placed in the same directory as the attachment
		 * they extend, because the file names produced here are later resolved
		 * against that directory. An attachment stored outside the uploads
		 * directory has no such directory to use, so there is nowhere the names
		 * this would produce could resolve.
		 */
		$attached_file = get_attached_file( $attachment_id, true );
		$subdir        = is_string( $attached_file ) && '' !== $attached_file
			? $this->get_attachment_upload_subdir( $attached_file )
			: null;

		if ( ! is_string( $attached_file ) || '' === $attached_file || null === $subdir ) {
			return new WP_Error(
				'rest_sideload_attachment_not_in_uploads',
				__( 'The attachment is not stored in the uploads directory, so a file cannot be sideloaded for it.' ),
				array( 'status' => 403 )
			);
		}

		if ( false === $request['convert_format'] ) {
			// Prevent image conversion as that is done client-side.
			add_filter( 'image_editor_output_format', '__return_empty_array', 100 );
		}

		// Get the file via $_FILES or raw data.
		$files   = $request->get_file_params();
		$headers = $request->get_headers();

		/*
		 * wp_unique_filename() will always add numeric suffix if the name looks like a sub-size to avoid conflicts.
		 * See /wp-includes/functions.php.
		 * With the following filter we can work around this safeguard.
		 */
		$attachment_filename = wp_basename( $attached_file );

		$filter_filename = static function ( $filename, $ext, $dir, $unique_filename_callback, $alt_filenames, $number ) use ( $attachment_filename ) {
			return self::filter_wp_unique_filename( $filename, $dir, $number, $attachment_filename );
		};

		add_filter( 'wp_unique_filename', $filter_filename, 10, 6 );

		// Pin the upload to the attachment's own directory, rather than deriving
		// it from the parent post's date as media_handle_upload() does for a
		// brand new upload. See the note above where $subdir is resolved.
		$filter_upload_dir = static function ( $uploads ) use ( $subdir ) {
			if (
				is_array( $uploads ) &&
				isset( $uploads['basedir'], $uploads['baseurl'] ) &&
				is_string( $uploads['basedir'] ) &&
				is_string( $uploads['baseurl'] )
			) {
				$uploads['subdir'] = $subdir;
				$uploads['path']   = $uploads['basedir'] . $subdir;
				$uploads['url']    = $uploads['baseurl'] . $subdir;
			}
			return $uploads;
		};

		add_filter( 'upload_dir', $filter_upload_dir, 100 );

		if ( ! empty( $files ) ) {
			$file = $this->upload_from_file( $files, $headers );
		} else {
			$file = $this->upload_from_data( $request->get_body(), $headers );
		}

		remove_filter( 'wp_unique_filename', $filter_filename );
		remove_filter( 'image_editor_output_format', '__return_empty_array', 100 );
		remove_filter( 'upload_dir', $filter_upload_dir, 100 );

		if ( is_wp_error( $file ) ) {
			return $file;
		}

		$type = $file['type'];
		$path = $file['file'];

		/** @var non-empty-string|non-empty-list<non-empty-string> $image_size */
		$image_size = $request['image_size'];

		/*
		 * Validate raster sub-sizes before storing them. Two companion sizes
		 * are exempt because wp_getimagesize() may not be able to read the
		 * file at all: the 'animated_video' companion of an animated GIF is a
		 * video (MP4/WebM), and a source-format original (e.g. a HEIC or JXL
		 * kept next to its JPEG derivative) may be an unreadable format. Their
		 * dimensions are neither validated nor recorded. The
		 * 'animated_video_poster' companion is a real image, so it is still
		 * read and rejected if unreadable; validate_image_dimensions() skips
		 * only the registered-size constraint for it.
		 */
		$skip_dimension_read = self::IMAGE_SIZE_SOURCE_ORIGINAL === $image_size || 'animated_video' === $image_size;
		$size                = false;

		if ( ! $skip_dimension_read ) {
			/*
			 * Read the dimensions up front. A file whose dimensions cannot be
			 * read is corrupted or an unsupported format and must be rejected
			 * rather than silently stored with zero dimensions.
			 */
			$size = wp_getimagesize( $path );

			if ( ! $size ) {
				// Clean up the uploaded file.
				wp_delete_file( $path );
				return new WP_Error(
					'rest_upload_invalid_image',
					__( 'Could not read image dimensions. The file may be corrupted or an unsupported format.' ),
					array( 'status' => 400 )
				);
			}

			/*
			 * Validate the dimensions against every size the file is being
			 * registered under. An array $image_size shares one file among
			 * several registered sizes, so the file has to satisfy each of
			 * them; validating only the scalar case would let a name wrapped
			 * in a one-element array skip the constraint entirely.
			 */
			foreach ( (array) $image_size as $size_name ) {
				$validation = $this->validate_image_dimensions( $size[0], $size[1], $size_name, $attachment_id );
				if ( is_wp_error( $validation ) ) {
					// Clean up the uploaded file.
					wp_delete_file( $path );
					return $validation;
				}
			}
		}

		// Build sub-size data to return to the client.
		// The client accumulates these and sends them all to the finalize
		// endpoint, which writes the metadata in a single operation. This
		// avoids the read-modify-write race that concurrent sideloads for the
		// same attachment would otherwise hit.
		$sub_size_data = array(
			'image_size' => $image_size,
		);

		if ( is_array( $image_size ) ) {
			/**
			 * Multiple registered sizes share these dimensions, so a single
			 * sideloaded file is reused for all of them. Arrays only carry
			 * regular sub-sizes; the special keys below are always scalar
			 * (ref. {@see self::get_special_image_sizes()}). Those never skip
			 * the read above, so $size already holds the dimensions.
			 */
			$sub_size_data['width']     = $size ? $size[0] : 0;
			$sub_size_data['height']    = $size ? $size[1] : 0;
			$sub_size_data['file']      = wp_basename( $path );
			$sub_size_data['mime_type'] = $type;
			$sub_size_data['filesize']  = wp_filesize( $path );
		} elseif ( self::IMAGE_SIZE_SOURCE_ORIGINAL === $image_size ) {
			/*
			 * Source-format original (e.g. the HEIC kept next to its JPEG
			 * derivative). Record the filename so finalize_item can store it
			 * under the dedicated source-image meta key.
			 */
			$sub_size_data['file'] = wp_basename( $path );
		} elseif ( 'animated_video' === $image_size || 'animated_video_poster' === $image_size ) {
			/*
			 * Converted-video companion of an animated GIF (the MP4/WebM or
			 * its static first-frame poster). Record the filename so
			 * finalize_item can store it under its dedicated meta key.
			 */
			$sub_size_data['file'] = wp_basename( $path );
		} elseif ( 'scaled' === $image_size || 'original' === $image_size ) {
			/*
			 * 'scaled' and 'original' both replace the attachment's main file
			 * with the supplied image and keep the file being replaced as
			 * `original_image`, which is the untouched upload. A 'scaled'
			 * image is downsized and an 'original' image has any EXIF
			 * orientation already applied. This is the same swap WordPress
			 * makes when it scales or rotates an image on upload; see
			 * _wp_image_meta_replace_original().
			 */
			$sub_size_data['original_image'] = $attachment_filename;

			// Validate the supplied image before updating the attached file.
			// $size was read above: neither of these sizes skips that read.
			$filesize = wp_filesize( $path );

			if ( ! $size || ! $filesize ) {
				// Clean up the uploaded file, which nothing references yet.
				wp_delete_file( $path );
				return new WP_Error(
					'rest_sideload_invalid_image',
					__( 'Unable to read the sideloaded image file.' ),
					array( 'status' => 500 )
				);
			}

			// Update the attached file to point to the supplied image.
			// This writes to _wp_attached_file meta, not _wp_attachment_metadata.
			if (
				$attached_file !== $path &&
				! update_attached_file( $attachment_id, $path )
			) {
				// Clean up the uploaded file, which nothing references yet.
				wp_delete_file( $path );
				return new WP_Error(
					'rest_sideload_update_attached_file_failed',
					__( 'Unable to update the attached file for this attachment.' ),
					array( 'status' => 500 )
				);
			}

			$sub_size_data['width']    = $size[0];
			$sub_size_data['height']   = $size[1];
			$sub_size_data['filesize'] = $filesize;
			$sub_size_data['file']     = _wp_relative_upload_path( $path );
		} else {
			// As above, $size was already read for every size reaching here.
			$sub_size_data['width']     = $size ? $size[0] : 0;
			$sub_size_data['height']    = $size ? $size[1] : 0;
			$sub_size_data['file']      = wp_basename( $path );
			$sub_size_data['mime_type'] = $type;
			$sub_size_data['filesize']  = wp_filesize( $path );
		}

		/*
		 * Record the file names produced for this attachment so finalize can
		 * confirm every stored sub-size was actually sideloaded here. The
		 * values recorded are exactly the ones handed back to the client, so
		 * finalize accepts a submission only when it echoes what was produced.
		 */
		foreach ( array( 'file', 'original_image' ) as $provenance_key ) {
			if (
				isset( $sub_size_data[ $provenance_key ] ) &&
				is_string( $sub_size_data[ $provenance_key ] ) &&
				'' !== $sub_size_data[ $provenance_key ]
			) {
				add_post_meta( $attachment_id, self::META_KEY_SIDELOAD_FILE_NAME, wp_slash( $sub_size_data[ $provenance_key ] ) );
			}
		}

		return rest_ensure_response( $sub_size_data );
	}

	/**
	 * Filters wp_unique_filename during sideloads.
	 *
	 * wp_unique_filename() will always add numeric suffix if the name looks like a sub-size to avoid conflicts.
	 * Adding this closure to the filter helps work around this safeguard.
	 *
	 * Example: when uploading myphoto.jpeg, WordPress normally creates myphoto-150x150.jpeg,
	 * and when uploading myphoto-150x150.jpeg, it will be renamed to myphoto-150x150-1.jpeg
	 * However, here it is desired not to add the suffix in order to maintain the same
	 * naming convention as if the file was uploaded regularly.
	 *
	 * The suffix is only dropped when no file of that name already exists in $dir,
	 * so this never returns a name that would overwrite one. The unsuffixed name
	 * must also derive from the attachment's own file name, and
	 * {@see self::sideload_item()} pins the upload to the attachment's own
	 * directory, so any name returned here belongs to the attachment being
	 * extended.
	 *
	 * @since 7.1.0
	 *
	 * @link https://github.com/WordPress/wordpress-develop/blob/30954f7ac0840cfdad464928021d7f380940c347/src/wp-includes/functions.php#L2576-L2582
	 *
	 * @param string      $filename            Unique file name.
	 * @param string      $dir                 Directory path.
	 * @param int|string  $number              The highest number that was used to make the file name unique
	 *                                         or an empty string if unused.
	 * @param string|null $attachment_filename Original attachment file name.
	 * @return string Filtered file name.
	 */
	private static function filter_wp_unique_filename( $filename, $dir, $number, $attachment_filename ) {
		if ( ! is_int( $number ) || ! $attachment_filename ) {
			return $filename;
		}

		$ext       = pathinfo( $filename, PATHINFO_EXTENSION );
		$name      = pathinfo( $filename, PATHINFO_FILENAME );
		$orig_name = pathinfo( $attachment_filename, PATHINFO_FILENAME );

		if ( ! $ext || ! $name ) {
			return $filename;
		}

		$matches = array();
		if ( preg_match( '/(.*)-(\d+x\d+|scaled)-' . $number . '$/', $name, $matches ) ) {
			$filename_without_suffix = $matches[1] . '-' . $matches[2] . ".$ext";
			if ( $matches[1] === $orig_name && ! file_exists( "$dir/$filename_without_suffix" ) ) {
				return $filename_without_suffix;
			}
		}

		return $filename;
	}

	/**
	 * Validates the `sub_sizes` file names against what this attachment produced.
	 *
	 * The {@see self::finalize_item()} method stores the client-supplied `file`
	 * and `original_image` values in the attachment metadata, where they are
	 * later resolved within the attachment's upload directory and read or deleted
	 * (for example by {@see wp_get_original_image_path()}, {@see wp_getimagesize()},
	 * and {@see wp_delete_attachment_files()}).
	 *
	 * Every file the sideload endpoint creates is recorded under
	 * {@see self::META_KEY_SIDELOAD_FILE_NAME} as it is produced, using
	 * server-generated names. finalize accepts a `file` or `original_image`
	 * value only when it matches one of those recorded names (or the
	 * attachment's own attached file, which it definitionally owns).
	 *
	 * @since 7.1.0
	 *
	 * @param int   $attachment_id The attachment being finalized.
	 * @param array $sub_sizes     Sub-size metadata collected from sideloads.
	 * @return true|WP_Error True if every file name was produced here, WP_Error otherwise.
	 *
	 * @phpstan-param list<Image_Sub_Size> $sub_sizes
	 */
	protected function validate_sub_size_provenance( int $attachment_id, array $sub_sizes ) {
		$allowed = $this->get_sideloaded_file_names( $attachment_id );

		foreach ( $sub_sizes as $sub_size ) {
			foreach ( array( 'file', 'original_image' ) as $key ) {
				/*
				 * Every value that was sent is checked, no matter how unlikely
				 * a name it looks. A loose emptiness test would wave through
				 * '0', which is a valid one-character name as far as the schema
				 * is concerned and is stored like any other. A value the schema
				 * types as a string but which arrives as something else is
				 * rejected rather than skipped, so a subclass which widens the
				 * schema cannot pass an unchecked value on to the metadata.
				 */
				if ( ! isset( $sub_size[ $key ] ) ) {
					continue;
				}

				if ( ! is_string( $sub_size[ $key ] ) || ! in_array( $sub_size[ $key ], $allowed, true ) ) {
					return new WP_Error(
						'rest_invalid_sub_size_file',
						__( 'Invalid sub-size file name. File names must have been produced by a prior sideload for this attachment.' ),
						array( 'status' => 400 )
					);
				}
			}
		}

		return true;
	}

	/**
	 * Returns the file names which a finalize request may store for an attachment.
	 *
	 * The set is the file names the sideload endpoint recorded as it produced
	 * them (ref. {@see self::META_KEY_SIDELOAD_FILE_NAME}), plus the attachment's own
	 * attached file - accepted in both its uploads-relative and basename form so
	 * a scaled main-file pointer validates regardless of which the client
	 * echoes - plus the names already stored in the attachment's own metadata.
	 *
	 * @since 7.1.0
	 *
	 * @param int  $attachment_id      The attachment being finalized.
	 * @param bool $include_provenance Whether to include the sideload provenance rows.
	 *                                 Pass false to get only the names recoverable from
	 *                                 the attached file and stored metadata, e.g. to decide
	 *                                 whether a provenance row is still needed. Default true.
	 * @return string[] File names that may appear in the finalize submission.
	 *
	 * @phpstan-return list<string>
	 */
	protected function get_sideloaded_file_names( int $attachment_id, bool $include_provenance = true ): array {
		$allowed = array();

		if ( $include_provenance ) {
			foreach ( (array) get_post_meta( $attachment_id, self::META_KEY_SIDELOAD_FILE_NAME ) as $name ) {
				if ( is_string( $name ) && '' !== $name ) {
					$allowed[] = $name;
				}
			}
		}

		$attached_file = get_post_meta( $attachment_id, '_wp_attached_file', true );
		if ( is_string( $attached_file ) && strlen( $attached_file ) > 0 ) {
			$allowed[] = $attached_file;
			$allowed[] = wp_basename( $attached_file );
		}

		/*
		 * Names already stored in this attachment's metadata passed this same
		 * check when they were written, so accepting them again introduces
		 * nothing new.
		 */
		$metadata = wp_get_attachment_metadata( $attachment_id, true );
		if ( is_array( $metadata ) ) {
			$stored = array(
				$metadata['file'] ?? null,
				$metadata['original_image'] ?? null,
				$metadata[ self::META_KEY_SOURCE_IMAGE ] ?? null,
				$metadata['animated_video'] ?? null,
				$metadata['animated_video_poster'] ?? null,
			);

			if ( ! empty( $metadata['sizes'] ) && is_array( $metadata['sizes'] ) ) {
				foreach ( $metadata['sizes'] as $size ) {
					$stored[] = is_array( $size ) ? ( $size['file'] ?? null ) : null;
				}
			}

			foreach ( $stored as $name ) {
				if ( is_string( $name ) && '' !== $name ) {
					$allowed[] = $name;
					$allowed[] = wp_basename( $name );
				}
			}
		}

		return array_values( array_unique( $allowed ) );
	}

	/**
	 * Returns the uploads subdirectory an attachment is stored in.
	 *
	 * Used to place a sideloaded file alongside the attachment it extends. The
	 * result is concatenated into a filesystem path by the caller, so it is
	 * returned only when the attachment resolves inside the uploads directory
	 * and the stored path is well formed.
	 *
	 * @since 7.1.0
	 *
	 * @param string $attached_file Absolute path to the attached file.
	 * @return string|null Subdirectory beginning with a slash, an empty string when the
	 *                     attachment sits in the base directory, or null when the
	 *                     attachment is not inside the uploads directory.
	 *
	 * @phpstan-param non-empty-string $attached_file
	 */
	protected function get_attachment_upload_subdir( string $attached_file ): ?string {
		$uploads = wp_get_upload_dir();
		if ( empty( $uploads['basedir'] ) ) {
			return null;
		}

		$basedir  = untrailingslashit( wp_normalize_path( $uploads['basedir'] ) );
		$file_dir = wp_normalize_path( dirname( $attached_file ) );

		/*
		 * The attachment's directory must be the uploads base directory itself
		 * or a directory inside it. The trailing slash in the prefix comparison
		 * keeps a sibling directory that merely shares the prefix (for example
		 * 'uploads-elsewhere' next to 'uploads') from matching.
		 */
		if ( $file_dir !== $basedir && ! str_starts_with( $file_dir, trailingslashit( $basedir ) ) ) {
			return null;
		}

		$subdir = (string) substr( $file_dir, strlen( $basedir ) );

		// A prefix match alone does not rule out a path that climbs back out.
		if ( in_array( '..', explode( '/', $subdir ), true ) ) {
			return null;
		}

		return $subdir;
	}

	/**
	 * Finalizes an attachment after client-side media processing.
	 *
	 * Applies the sub-size metadata collected from sideload responses in a
	 * single metadata update, then triggers the 'wp_generate_attachment_metadata'
	 * filter so that server-side plugins can process the attachment after all
	 * client-side operations (upload, thumbnail generation, sideloads) are
	 * complete.
	 *
	 * @since 7.1.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function finalize_item( WP_REST_Request $request ) {
		$attachment_id = (int) $request['id'];

		$post = $this->get_post( $attachment_id );
		if ( is_wp_error( $post ) ) {
			return $post;
		}

		/**
		 * Sub-size metadata collected from sideload responses. Confirm every
		 * file name was produced by a prior sideload for this attachment before
		 * storing it, so a client cannot make finalize record (and later read or
		 * delete) another attachment's files.
		 *
		 * @var list<Image_Sub_Size> $sub_sizes
		 */
		$sub_sizes  = $request['sub_sizes'] ?? array();
		$provenance = $this->validate_sub_size_provenance( $attachment_id, $sub_sizes );
		if ( is_wp_error( $provenance ) ) {
			return $provenance;
		}

		$metadata = wp_get_attachment_metadata( $attachment_id );
		if ( ! is_array( $metadata ) ) {
			$metadata = array();
		}

		// Apply all sub-size metadata collected from sideload responses.
		foreach ( $sub_sizes as $sub_size ) {
			$image_size = $sub_size['image_size'];

			// When multiple size names share identical dimensions the client
			// sends a single sub-size entry with an array of names. Register the
			// same file under each name.
			if ( is_array( $image_size ) ) {
				/*
				 * Arrays carry regular sizes only, as the sideload endpoint
				 * enforces. Each special size names a single file handled by one
				 * of the branches below, so grouping one under a shared file
				 * would write it to the wrong place; reject rather than guess.
				 */
				if ( array_intersect( $image_size, self::get_special_image_sizes() ) ) {
					return new WP_Error(
						'rest_invalid_sub_size_name',
						__( 'A grouped sub-size entry may only name regular image sizes.' ),
						array( 'status' => 400 )
					);
				}

				// As below: `file` is not required by the schema, and a size
				// entry that names no file is not worth recording.
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				$metadata['sizes'] = $metadata['sizes'] ?? array();

				foreach ( $image_size as $name ) {
					$metadata['sizes'][ $name ] = array(
						'width'     => $sub_size['width'] ?? 0,
						'height'    => $sub_size['height'] ?? 0,
						'file'      => $sub_size['file'],
						'mime-type' => $sub_size['mime_type'] ?? '',
						'filesize'  => $sub_size['filesize'] ?? 0,
					);
				}
				continue;
			}

			if ( 'original' === $image_size || 'scaled' === $image_size ) {
				// Skip malformed entries so a bad payload cannot blank out the
				// main file metadata.
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				/*
				 * Record the supplied full-size image (from sideload_item()) as
				 * the main file, keeping the current attached file as
				 * `original_image`. A 'scaled' image is downsized and an
				 * 'original' image is rotated; both have any EXIF orientation
				 * already applied by the client.
				 */
				if ( ! empty( $sub_size['original_image'] ) ) {
					$metadata['original_image'] = $sub_size['original_image'];
				}
				$metadata['width']    = $sub_size['width'] ?? 0;
				$metadata['height']   = $sub_size['height'] ?? 0;
				$metadata['filesize'] = $sub_size['filesize'] ?? 0;
				$metadata['file']     = $sub_size['file'];

				/*
				 * The supplied image has its orientation applied already, so
				 * reset the stored value (from the upload) to 1, as
				 * wp_create_image_subsizes() does for both its scale and rotate
				 * paths. Otherwise exif_orientation would still report the
				 * pre-rotation value and the client would rotate the image
				 * again on a re-fetch.
				 */
				if ( ! empty( $metadata['image_meta']['orientation'] ) ) {
					$metadata['image_meta']['orientation'] = 1;
				}
			} elseif ( self::IMAGE_SIZE_SOURCE_ORIGINAL === $image_size ) {
				// As above: `file` is not required by the schema, and each of
				// these sizes is nothing but the file it names.
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				/*
				 * Source-format original: stored under its own meta key so the
				 * scaled-sideload flow (which writes 'original_image') cannot
				 * clobber it. 'original_image' keeps pointing at the
				 * web-viewable JPEG derivative. Cleanup on attachment delete
				 * is handled by wp_delete_attachment_files().
				 */
				$metadata[ self::META_KEY_SOURCE_IMAGE ] = $sub_size['file'];
			} elseif ( 'animated_video' === $image_size ) {
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				/*
				 * Converted-video companion of an animated GIF. Stored under its
				 * own meta key; 'original_image' keeps pointing at the GIF. Cleanup
				 * on attachment delete is handled by wp_delete_attachment_files().
				 */
				$metadata['animated_video'] = $sub_size['file'];
			} elseif ( 'animated_video_poster' === $image_size ) {
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				// Static first-frame poster for the converted video.
				$metadata['animated_video_poster'] = $sub_size['file'];
			} else {
				if ( empty( $sub_size['file'] ) ) {
					continue;
				}

				$metadata['sizes'] = $metadata['sizes'] ?? array();

				$metadata['sizes'][ $image_size ] = array(
					'width'     => $sub_size['width'] ?? 0,
					'height'    => $sub_size['height'] ?? 0,
					'file'      => $sub_size['file'],
					'mime-type' => $sub_size['mime_type'] ?? '',
					'filesize'  => $sub_size['filesize'] ?? 0,
				);
			}
		}

		/** This filter is documented in wp-admin/includes/image.php */
		$metadata = apply_filters( 'wp_generate_attachment_metadata', $metadata, $attachment_id, 'update' );

		wp_update_attachment_metadata( $attachment_id, $metadata );

		/*
		 * Drop only the provenance rows this request consumed, now that the
		 * names are recorded in the metadata itself. A row is dropped only once
		 * its name is recoverable from the stored metadata, so a name the
		 * 'wp_generate_attachment_metadata' filter removed - or that a failed
		 * update never persisted - keeps its row and the retried request the
		 * endpoint documents as idempotent still validates. Rows for sideloads
		 * that have not been finalized yet survive for a later call, and passing
		 * the value makes the delete a no-op when the row is already gone, so a
		 * retried request cleans up without error. Any rows left behind by an
		 * abandoned upload are removed with the attachment itself.
		 *
		 * Retrying is idempotent for the request as it was sent. A name is only
		 * unavailable to a retry once a later finalize has overwritten the same
		 * size with a newly sideloaded file, which drops the earlier name from
		 * the metadata the retry recovers it from.
		 *
		 * The names are collected before deleting so a request which repeats
		 * the same name across many sub-sizes still issues one query per
		 * distinct name.
		 */
		$recoverable = $this->get_sideloaded_file_names( $attachment_id, false );
		$consumed    = array();
		foreach ( $sub_sizes as $sub_size ) {
			foreach ( array( 'file', 'original_image' ) as $key ) {
				// Matches the set validate_sub_size_provenance() checked, so
				// every name a request was allowed to store is also cleaned up.
				if (
					isset( $sub_size[ $key ] ) &&
					is_string( $sub_size[ $key ] ) &&
					in_array( $sub_size[ $key ], $recoverable, true )
				) {
					$consumed[] = $sub_size[ $key ];
				}
			}
		}

		foreach ( array_unique( $consumed ) as $file_name ) {
			delete_post_meta( $attachment_id, self::META_KEY_SIDELOAD_FILE_NAME, wp_slash( $file_name ) );
		}

		$response_request = new WP_REST_Request(
			WP_REST_Server::READABLE,
			rest_get_route_for_post( $attachment_id )
		);

		$response_request['context'] = 'edit';

		if ( isset( $request['_fields'] ) ) {
			$response_request['_fields'] = $request['_fields'];
		}

		return $this->prepare_item_for_response( $post, $response_request );
	}
}
